9. BLACK SUN

WHEN I COME OUT OF THE CELLAR CLUTCHING MY grisly handbag, Hutter and Mo are gone. Chaitin is stooging around, shuffling from foot to foot as he waits for me. "Let's go," he says, so I heft the bag at him.

"Got it." We head back up the corridor past the glow-tubes and I glance over my shoulder just once,

breath steaming in the frigid air. Then I lower my visor and lock it in place, check my regulator, and listen to the hiss of cool air through my helmet. "Where is everybody?"

"Boss man's up top arming the gadget; your squeeze is on her way back to the gateway."

"Great," I say, and I mean it. This place is getting to me; I almost want to dance a little jig at the thought of blowing it to atoms. "Did anybody find any documentation?"

"Documentation? Tons of it. These guys were Germans, dude. You ever worked with the fucking Wehrmacht, you'd be able to tell a story about documentation, too."

"Huh." We hit the bottom of the stairs. Scary Spice is waiting for us.

"Go on up," he says to Chaitin. He stops me: "You, wait." He twists a dial on my chest pack: "Hear me?"

"Yeah," I say, "loud and clear. Has anyone seen any sign of the bastard who kidnapped Mo?"

"The target, you mean?" Scary hefts his heavily insulated gun and for a moment I'm glad I can't see through his face mask. "Naah, but you're going up the stairs right now and I'm following you, and if you see anyone behind me yell like hell."

"That," I say fervently, "is fine by me." Already the shadows are lengthening as the glow-tubes slowly burn out.

There's crosstalk and terse chatter all over the radio channel Scary has tuned me to; I get the impression of three teams retreating to prearranged positions, keeping their eyes peeled for company. Some evil bastard demon has been here in the past couple of hours, wearing a stolen body: Can't we move faster? Evidently not. "Timer set to seven thousand seconds by my mark," Alan cuts in on the common channel. "This is your hundred and ten minute warning, folks. I've pulled the spoiler chain and the initiator is now live; anyone still here in two hours better have some factor one-billion sunblock. Sound off by name."

Everyone seems to be accounted for, except the three outside. "Okay, pull out in LIFO order. Scary, Chaitin, make sure Howard's in tow and cycle when ready."

"Right, boss." Chaitin. "C'mon, you, let's go."

"Okay." I wait while Chaitin cycles through the airlock into the garage, then open the door and squeeze into the cramped closetlike space. "I'm on tank one, everything working."

"It better be. Okay, cycle yourself through."

I wait for a tense two minutes while the air hisses out of a tiny tube and I feel the pressure suit tightening around me. Oddly, I begin to feel warmer once I'm in partial vacuum; the chilly air in the redoubt was sapping my body heat. Presently the outer door swings open. "Move, move!"

I walk out into the garage, open doors gaping at the ink-black sky, then out into the courtyard in front of the building. Chaitin's waiting there. Someone's parked that electric trolley next to the wall, but the little half-track thing with a motorcycle's front wheel is missing. "Someone taking souvenirs?" I ask.

A burst of static that I just about decode as "What?" tells me that the interference is worse than before; I glance up and see red stars, a dull red swirl of galaxy overhead… a distinct pink tinge to the moon, in fact.

I point at where the Kettenkrad was parked. "There, it's gone," I say. "Who took it?"

Chaitin shrugs. I look round. "Go there." He points at the main gatehouse. I start walking. The moonlight is dim, rosy: either I'm reeling lightheaded or… or what?

It's about a kilometre to the wall where our unseen enemy opened the gate to Amsterdam, and with no sign of him in the vicinity I have time to do a little bit of thinking. Looking straight up I see only darkness; the visible stars mostly stretched in a wide belt above the horizon, the moon an evil-faced icon staring down at us. The power to suck all the life and heat out of a planet like this—it's horrifying. While a sacrificial murder will get you a hot-line to a demon capable of possessing you, or a window to some universe so alien you can't comprehend its physical laws, it takes a lot of power to open a physical gate to another version of the Earth. Shadow Earths interfere with each other, and it's very difficult to generate congruence. But whatever happened here…

I try to picture what might have happened. I can only come up with two scenarios:

Scenario one. An Ahnenerbe detachment in Germany, some time in April of 1945. They know they're losing, but defeat is not an acceptable option to them. They quickly gather all the supplies they can: foodstuffs, machine tools, seeds, fuel. Using a handful of captured enemy POWs, a gate is opened to somewhere cold and airless where they can wait out the hue and cry before making a break for home.

Nope, that doesn't work. How'd they build this fortress? Or mess with the moon?

Scenario two. A divergent history; a different branch of our own universe, so close to our own timeline that the energy it takes to open a full bridge between the two realities approximates the mass-energy of the universe itself. The point of departure, the fork in the river of time, is an invocation the Ahnenerbe attempted late in the war—but not too late. It's an act of necromancy so bloody that the priests of Xipe Totec would have cringed in horror, so gruesome that Himmler would have protested. They opened a gateway. We thought it was just a tactical move, a way to move men and materials about without being vulnerable to Allied attack—shunt them into another world, travel across it bypassing their enemies, then open a gateway back to our own continuum. But what if they were doing something more ambitious? What if they were trying to open a channel to one of the nameless places where the infovores dwell: beings of near-infinite cold, living in the darkened ghosts of expanded universes that have succumbed to the ancient forces of proton decay and black hole evaporation? Invoking Godlike powers to hold their enemies at bay, the forces of the Red Army and the Western Allies are held in check…

What happened next?

Pacing through the petrified forest I can see it as clearly as a television documentary. A wind of desolation and pain screams out of the heart of Europe, hurling bombers from the skies like dandelion seeds. A darkness rises in the west, a maelstrom that sucks Zukhov's divisions in like splinters of a shattered mast sent flying in a hurricane. The SS necromancers are exultant: their demons harrow the Earth in stolen bodies, scouring it clean of enemy forces, eating the souls of the untermenschen and spitting up their bones. Snow falls early as fimbulwinter sets in, for the ice giants of legend have returned to do the bidding of the thousand-year Reich, and the Führer's every dream shall be made real. A pale sun that warms nothing gazes down across a wilderness of ice and fire, ravaged by the triumph of the will.

They only realise how badly they'd miscalculated some months later as the daylight hours shorten, and shorten further—until the equinox passes, the temperature continues to fall as the sunlight dims, and the giants cease to do their bidding.

Götterdämmerung has come for the victorious Third Reich…

Up the low rise with the wall on the other side, I turn round and look back at the redoubt, at the last island of warmth in a cold world that's been sucked dry. I contemplate it for a minute or so. "Had a thought," I say aloud, and get a burst of static in return.

I look round. Chaitin is standing farther up the hillside; he waves at me. More static. "You there?" I ask, fiddling with my radio controls. "Can you hear me?"

He walks toward me, brandishing something. I focus on a coil of cable with a plug on the end, but as he approaches the static begins to clear up. He pokes it at my chest pack but I bat his hand away. "Speak," he says roughly.

I take a deep breath: "I need to make some measurements. There is something very, very wrong with this whole picture, you know? Why is it so cold? Why are our suit radios all malfunctioning? What killed everyone in that bunker? Seems to me that Alan needs to know. Hell! I need to know—it's important."

Through his suit helmet Chaitin's expression is unreadable. "Explain."

I shiver with a sudden realisation. "Look, they summoned something that hunkered down and sucked all

the fucking energy out of this universe, and if Alan sets off an H-bomb—what do you think is going to happen?"

"Talk more." Chaitin offers me the cable again.

I point to my damaged chest pack, then point my finger straight up. "Look, the stars are all reddish, and they're too far apart. That's number one. Red shift means they're all flying away from each other like crazy! That, or the energy in the light they're emitting is being sapped by something. I figure that effect is also what's screwing with our radios: in this universe the Planck constant is changing. Number two, the sun—the sun's gone out. It went out a few decades ago, that's why the temperature's down to forty absolute and dropping; the only thing keeping the Earth above cosmic background temperature is the fact that it's a honking great reservoir of hot rocks, with enough thorium and uranium mixed in that decay heat will keep it simmering for billions of years. But that's losing energy faster than it should, too, because something here is distorting the laws of physics. Third: for all we know all the other suns have gone out, too—the light we see from the stars is fossil radiation, it's been travelling for years, centuries."

I take a deep breath and shift my feet. Chaitin isn't saying anything; he's just looking around, looking for signs in the sky or the earth. "Something is eating energy, and information," I say. "Our primary objective—in coming here—is to find out what's going on and report back. I'm saying we haven't found out yet, and what the captain doesn't know can hurt us all."

Chaitin turns back to face me.

"It makes sense, doesn't it?" I say. "Like, it all hangs together?"

He holds up a torch to illuminate his face through his visor. He's grinning at me with a face I haven't seen before: "Sehr gut," he says, then he drops the torch, releases the catches, and lifts his helmet off. Luminous worms of light writhe soundlessly behind his eyelids, twisting in the empty space of his skull, just like the thing that took Fred from Accounting. The out-gassing air from his suit wreathes him in vapour as he leans toward me, grabbing, trying to make a close flesh-to-flesh contact seeing as his comms-cable gambit has failed. Just one moment of electrical conduction-

The thing that occupies Chaitin's skin and bone is not very intelligent: it's forgotten that I'm wearing a suit, too, and that these suits are designed to take a fair bit of abuse. Still, it's pretty freaky. I drop my sack and hop backward, nearly going arse-over-ears as gravity seems to suck at my backpack. The possessed body scrabbles toward me and I can see, very clearly, a trickle of blood bubbling from his nose as I fumble for the basilisk gun at my waist, grab onto it with both hands, and punch both red buttons with my thumbs. For a panicky moment I think that it's dead, batteries drained by the chilling cold out here—then all hell breaks loose.

Roughly one in a thousand carbon nuclei in the body that used to belong to Chaitin spontaneously acquire an extra eight protons and seven or eight neutrons. The mass deficit is bad enough—there's about as much energy coming out of nowhere as a small nuke would put out—but I'll leave that to the cosmologists. What's bad is that each of those nuclei is missing a whopping eight electrons, so it forms a wildly unstable carbosilicate intermediary that promptly grabs a shitload of charge out of the nearest electron donor molecules. Then it destabilizes for real, but in the process it's set off a cascade of tiny little acid/base reactions throughout the surrounding hot chemical soup that used to be a human body. Chaitin's body turns red, the kind of dull red of an electric heating element—then it steams, bits of his kit melting as his skin turns black and splits open. He begins to topple toward me and I yell and jump away. When he hits the ground he shatters, like a statue made of hot glass.

The next thing I know I'm on my knees on the frozen ground, breathing deeply and trying desperately to tell my stomach to be still. I can't afford to throw up because if I vomit in my face mask I will die, and then I won't be able to tell Alan what kind of mistake he'll be making if he sets off the demolition charge.

This whole world has been turned into a mousetrap: a body-snatching demon, patient and prepared, waiting for us little furry folk with beady black eyes to stick our curious noses inside.

I pick myself up, watching the steamy vapour pour from the ground around the molten depressions my kneepads melted in the permafrost as I take more deep, laborious breaths. Static ebbs and flows in my ears like bacon frying, the distorted sidebands of a transmission counting down the minutes to the artificial sunrise. I try not to look at what's left of Chaitin.

They summoned an infovore: something that eats energy and minds. A thing—I don't know what sort-from a dead cosmos, one where the stars had long since guttered into darkness and evaporated on a cold wind of decaying protons, the black holes dwindling into superstring-sized knots on a gust of Hawking radiation. A vast, ancient, slow thinker that wanted access to the hot core of a youthful universe, one mere billions of years from the Big Bang, poised for a hundred trillion years of profligate star-burning before the long slide into the abyss.

On my feet now, I check my air supply: good for two and a quarter hours. That will see me through—the bomb's going to blow in just over an hour. I look round, trying to work out which way to go. Thoughts are clamouring in my head, divergent priorities-

The thing was hungry. First it did what it was invited to do, sucked the minds and life from the Ahnenerbe's enemies, occupied their bodies, and learned how to pass for human. Then it pulled more of itself through the gate than they'd expected. It's big—far too big to fit through a man-sized gate—but it had access to all the energy it wanted, and all the minds to sacrifice, more than enough power to force it wide open and squirm through into this new, rich cosmos.

The monster they summoned gave the Ahnenerbe more than they asked for. As well as damping the fusion phoenix at the heart of every star, it started to drain energy directly out of spacetime, messing with the Planck constant, feeding on the false vacuum of space itself. Light stretched, grew redder; the gravitational constant became a variable, dropping like a barometer before a storm. Fusion processes in the sun guttered and died, neutrons and protons remaining stubbornly monogamous. The solar neutrino flux disappeared first, though it would take centuries for the sun itself to show signs of cooling, for the radiation-impeded gravitational collapse to a white dwarf core to resume. Meanwhile, the universe began to expand again, prematurely ageing by aeons in a matter of years.

Back to the here-and-now. Here I am with a corpse. And a gun. And the corpse manifestly killed using the gun in my hands. Shit. I twiddle the squelch on my radio but get nothing but loud hissing and incoherent bursts of static. What am I going to tell Alan—"Look, I know I appear to have shot one of your men, but you've got to abort the mission"?

I glance up at the sky. It's night, but maybe the sun would be visible if I knew where to look. Visible-and shrunken, farther away than it is back home, for as the creature sucks energy out of spacetime, space itself is getting bigger, and emptier. Losing energy. Find Alan. Stop the bomb. Get everybody out fast. It took a lot of energy for the thing to fully open the gate to its original home and bring itself through to this shattered Earth; energy that is no longer available in this drained husk of a universe, energy that it needs if it's to move on to pastures new. About all it's capable of on its own right now was to listen for an invitation—from the terror cell in Santa Cruz—and answer their call. What will it do if we dump more energy into it? Open a gate back to its original home? Expand the gate to our Earth? There's a worstpossible-case scenario here that I don't even want to think about—I'm going to have nightmares about it for years, if I have any years ahead of me to have nightmares in.

Having dragged its huge, cold presence through to squat in the ruins of the victorious Reich, it settled down to wait: patient, for it has waited for an infinity of infinities already, waiting for a hot, fast thinker to open the gate to the next universe. Focussed in one place, it will be able to move far faster this time-no need for a sacrifice of millions to get its attention. Once invited—by the clever stupidity of a terrorist cell, perhaps—it can take possession of a body and, using what it has learned of the nature of humanity from the Ahnenerbe-SS, manipulate those around it. The possessed, its agent on the other side of that first gate, must arrange to open a connection, then find an energy source to crack it wide open, big enough to admit the rest of the eater. Opening a gate wide enough for a human body, with an agent at both ends, would take about as much energy as it had left—the lives of all the remaining Ahnenerbe-SS survivors in this world, hoarded against such an eventual need. But to open a gate so that it can admit an ice giant—a being big enough to carve monuments on the moon and suck dry a universe—will take much more energy: energy gained from either a major act of necromancy or a singularly powerful local source.

I look around. I'm at the foot of a hill; on the other side of it there's a wall, and a couple of pathetic corpses, and half a platoon of SAS specialists. Behind me there's a petrified forest and a castle of shadows, populated with nightmares. (Oh, and a hydrogen bomb that's going to go off in about seventy minutes.) Where is everybody? Strung out between the castle and the gate, that's where.

Got to tell Alan not to set off the bomb. I pick up my sack of hands and stagger downhill toward the skeletal trees, feet and ankles tensed with that walking on glass sensation you get when you're afraid there's nothing but black ice underfoot, one hand clutching the basilisk gun at arm's reach. Branches claw at me in the twilight, making me flinch inside my helmet; they snap and tinkle against my visor, rigid bundles of mummified twigs with all the heat sucked out of them. If there's more than one of the body snatchers here…

I skid and go down on one thigh, hard. Something crunches underfoot, like twigs snapping. I lever myself upright, rub my leg and wince, breath loud in my ears. Looking down I see a hump of frozen brown, a small rabbit or a rat or something else that's been dead for years. Dead. I stoop and pick up my bag of severed hands, tagged for identification at a later date. Wouldn't this be a good time to think about precautions? In case there are other demons stalking this frozen plain in stolen bodies?

Well, yes. I cast a glance in the direction of the redoubt, racking my brains for a half-forgotten lecture on occult stealth technologies.

FIFTEEN MINUTES LATER—TEN PRECIOUS MINUTES of which expire in a feverish rush of poking clumsily at a severed ulna and radius with my multitool and a roll of duct tape—I'm standing in the middle of the dead ground in front of the redoubt. Things have clearly gone very pear-shaped indeed. I clutch the talisman like a drowning man and try to figure out what to do now.

(The talisman glows dimly, an eerie blue light chewing away at the fingertips. To get it lit, I used the basilisk gun on a tree stump and thrust it against the glowing coals. The deep incisions in the palm are the red of firelight reflected in freshly spilt blood. I grip the grisly artifact by its exposed wrist bones and hope like hell that it performs as advertised. See, if you stick a phase-conjugate mirror on the base of a Hand of Glory you can make it spit light; but that's a modern perversion of its original function… )

Overhead, the stars are going out one by one. The moon is a blood-soaked red disk; shadows are creeping across the landscape, settling across the hills I can glimpse through my night-vision goggles. And something like a fire is burning on the roofline above the last redoubt of the Ahnenerbe-SS: What's going on?

I try the radio again. "Howard to anyone, anyone still out there, please respond." The hissing, frying interference crashes in on my ears, obscuring any answer. I stumble forward on the icy ground just as something that might once have been human dashes around the side of the building, heading in the direction of the gate. It doesn't see me, but someone inside sees it: sparks blossom on the cold ground behind it, and I see brief muzzle flashes coming from a window-slit on the second floor. It was one of ours originally, but no human being can sprint around a building with their helmet off and backpack missing in a fimbulwinter cold enough to freeze liquid oxygen.

The possessed soldier raises something blocky to its shoulder and sprays cartridge cases all over the night. Maybe one or two of the bullets come close to the upstairs window, but if so they don't stop whoever's upstairs from catching it with their next burst: for a moment it capers across the ice, then it flops down and lies still. "Shit," I mutter, and find myself stumbling into a clumsy trot toward the gaping garage door with its welcoming airlock.

Nobody shoots at me; the talisman is doing its job, fogging the senses of anyone who can see me. I skid to a halt just outside, a nasty suspicion blossoming in my mind, and very carefully inspect the threshold. Yup, there it is: a black box taped to the wall, thin wire stretched taut across the threshold at knee level. Some wag has stencilled THIS SIDE TOWARD LIFE INSURANCE CLAIMANT on its case. I very carefully step over the tripwire then try the radio again. "Howard to anyone. What's going on? Who's shooting?"

A crackling whine flattens the answer, but at least this time there is one: "Howard! What's your condition? Report." I try to remember who it is, those clipped tones: Sergeant Howe.

"I'm in the garage with a Hand of Glory," I say. I swallow. "It got Chaitin while I wasn't watching him, but I got away—shot it while it was trying to assimilate me. A demon, that is. They take possession if they can touch you—it takes skin-to-skin or electrical contact. There was more than one out here but I'm not sure any are still up. I improvised a stealth talisman to get me back in here; you've got to put me through to Alan, immediately."

"Wait right there." He sounds tense. "You in the garage?"

I try to nod, then answer: "Yeah, I'm in the garage—I spotted the spring surprise in time. Look, this is urgent; we've got to disable the demo gadget before we get out of here. If it blows—"

The outer airlock door edges open. "Get your ass in the airlock now, Howard. Close and lock the door. When it cycles, put anything you're carrying down and raise your arms. When the door opens, don't move until I say so. Don't even breathe until I say so. Got it?"

"Got it," I say, and open the airlock door. I freeze—then carefully put the Hand of Glory down outside the lock, power down the basilisk gun and isolate the charge circuit, drop the sack of severed hands, and make sure my palmtop is asleep before I look inside the chamber again. I swallow. There's a green spheroid taped to the inner door, a fine wire stretching from one end to the rubberised gasket that seals the lock. Below it, there's another gadget: a thaumometer, a sensor that monitors spatiotemporal disturbances indicative of occult activity. That, too, has a wire vanishing inside the gasket. I swallow again. "I'm stepping inside the lock now," I say. My legs don't want to move. "I'm closing the outer door."

I tell myself I know Alan, and he's not going to do anything stupid. I tell myself that Sergeant Howe is a professional. Locking myself in a room the size of a shower cubicle with a live hand grenade on the end of a string still gives me the cold shudders.

Air hisses through vents and I raise my arms, stiffly forcing the suit to comply. At the last moment I think to turn and make sure that I'm leaning against the side of the lock, not facing the inner door. Then the door clicks—audible, there must be air pressure inside—and swings open. Someone is kneeling outside, pointing a gun at me from behind a body that's sprawled on the floor right in front of the lock.

"Bob." It's Alan. "If that's you, I want you to tell me who else was in the classroom with us."

Phew. "It was taught by Sophie, and we were in it with Nick from CESG."

"That's good. And you're still wearing your helmet. That's good, too. Now I want you to turn around slowly, keeping your hands up—that's right. Now, I want you to slowly raise your visor. Hold it—keep your hands still." The guy with the gun keeps it levelled on my face. Mo was right: I never realised you could see the grooves—lands—of a rifle barrel at three metres; it looks huge, large enough to drive a freight train down.

Something jabs at my left leg and I nearly stumble, then: "He's clean," announces someone who was right next to me all the time—I never noticed—and I lower my arms. The guy who's been keeping me covered points his gun at the floor, and suddenly I'm breathing normally again.

"Where's Alan?" I ask. "What's been happening here?"

"I was hoping you could tell me," Alan says in my left ear. I look round and he grins tensely. The grin doesn't reach his eyes, which are the colour of liquid oxygen and just as warm. "Tell me exactly what happened to you when you went outside. Tell it like your life depends on it."

"Uh, okay." I shuffle away from the lock door and someone—Scary Spice?—swings it shut again.

I spill the beans, including the way Chaitin jumped me. I figure they already know that something's taking over brains and bodies wherever possible. My eyes keep being drawn back to the floor. It's Donaldson, the guy who was speculating about meteorology earlier. He doesn't look real, somehow, as if he ought to get up and walk away in a minute or two, peel off the rubber gore applied by the special effects people and have a laugh with us over a pint. "I figure the whole thing is a trap," I finish. "We were lured here deliberately. Only one of the possessors came through to our world, and it could only control one body at a time, but there may be more here. They're working for, or are part of, something that's not human, but that's had years to study us—to study the survivors from the Ahnenerbe-SS. It took over some useful idiots who tried to summon it from our side in order to use it for a terrorist incident; then it stalked us, kidnapped Mo as bait. It did that because it wants us to provide a power source that'll allow it to expand the gate and push its main body through into our universe. It's a lot bigger than the possessors we've seen so far—it's, like, it's achieved a limited beachhead but it needs to grab an entire harbour from the defenders—us—before it can land the main body of its forces."

"Right." Alan looks pensive. "And how do you think it's going to do this?"

"The demolition gadget. What yield have you set it to?" I ask.

Howe raises an eyebrow. "Tell him," says Alan.

"It's a selective yield gadget," says Howe. "We can set it to anything from fifteen kilotons to a quarter of a megaton—it's a mechanical process, screw jacks adjust the gap between the fusion sparkplug and the initiator charge so that we get more or less fusion output. Right now it's at the upper end of the yield curve, dialled all the way up to city-buster size. What's this got to do with anything?"

"Well." I lick my lips; it's really cold in here now and my breath is steaming. "To open a gate big enough to bring through a large creature like whatever ate this universe takes a whole lot of entropy. The Ahnenerbe did it in this universe by ritually murdering roughly ten million people: information destruction increases entropy. But you can do it in other ways—an H-bomb is a really great entropy and energy generator, it minimizes the information content of lots of stuff." They look blank: I glare at them. "Look, it's the intersection between thermodynamics and information theory, right? Information content is inversely proportional to entropy, entropy is a measure of how well randomized a system is—that's one of the core assumptions of magic, right? That you can transfer energy between universes via the platonic realm of ordered information—mathematics. I think what this monster has been doing all along was raising enough hell via its minor agents to provoke a response—one in which we'd lash out, giving it all the juice it needs to expand the gate. As it is, the minor gate it yanked Mo through is shrinking; I figure that was all it could manage. It's drained so much energy from this universe already that it had to wait for precisely the right moment before it dared open that one; this place is falling apart, and there may not be enough power for the monster to open even one more minor gate. Have you noticed how the stars are going out and we're getting radio interference? I think what we're seeing is fossil starlight—what's left of this universe may only be a bit larger than the solar system, and it's shrinking at close to light-speed. Give it another few hours and it'll collapse like a soap bubble, taking the ice giant with it. Unless we feed it, or them, or whatever the hell it is, enough energy to shore open the gate to our own world and expand it until they can squeeze through."

"Ah." Alan looks as if he's just swallowed something unpleasant. "So. It's your considered opinion that our best course of action would be to disable the bomb and retire, hmm?"

"That's about the size of it," I agree. "Where did you plant the gadget anyway?"

"Downstairs; but that's a bit of a sore point," Alan comments airily. "The bomb's armed and we've switched over from manual detonation control via the dead man's handle to the internal timer. But there's a catch. You see, Her Majesty's Government doesn't really like the idea of leaving armed hydrogen bombs lying around the place without proper supervision. PAL control is fine, and so is a detonation wire and dead man's handle, but these things are designed in case they might get overrun, and we wouldn't want to hand an H-bomb on a plate to some random troublemaker, what?"

Alan begins to pace. Alan pacing, that's a bad sign. "Once we've inserted the initiator, dialled a yield, armed the detonators, punched in the permissive action codes, set the timer, then removed the control wires, nothing's going to stop it. Can't even open it up: someone messes with the tamper piece, it calls 'tilt' and the game's over. Y'see, we might be a Soviet Guards Motor Rifle formation that's just captured the bridge it's strapped to. Or a bunch of uglies from the backwoods behind the Khyber Pass. So, as you can understand, even conceding that letting it blow here and now might be a very bad idea, it's going to go. Unless you fancy trying your hand at dissecting a booby-trapped, ticking H-bomb, and I don't recall seeing UXB training on your résumé."

He glances at his watch. "Only another fifty-seven minutes to go, lad. We can probably make it to the gate if we leave in less than half an hour, as long as there aren't too many of the blighters left outside—so I'd hurry up if I was you."

"Could we take it with us?" I ask.

He barks a short laugh. "What, you think they'd thank us for dragging a live quarter-megaton bomb back into one of the most densely populated cities in Europe?"

"They can't stop it then?"

"Take an act of God to stop it now," Howe says with gloomy satisfaction. "Take an act of God to get us all out of here alive, too. Bet you're wishing you hadn't come back!"

I lick my lips, but my tongue seems to have turned to dry leather. Leathery, like one of Brains's weirdly scrambled-in-its-own-shell eggs. Which reminds me: suddenly what I have to do comes crystal clear. "I think I know how to get your people out regardless of whether there are any revenants outside," I say. "Same way I got in here without anyone spotting me. As for the bomb—what if just a bit of the implosion charge goes off prematurely? Say, at one end of it?"

Alan looks at me oddly. "How are you going to do that?"

"Never mind. What happens if? If, if. Way I remember it, all nuclear weapons these days use a core of plutonium and a set of shaped charges that interlock around it. When they go off, they have to be really precisely timed or the core doesn't implode properly, and if it doesn't implode it doesn't reach critical mass, and if it doesn't go supercritical it doesn't go bang. Right?" I'm almost bouncing up and down. "There's some stuff I need just outside the airlock—a bag of severed hands, a basilisk gun. I've got the rest of the kit here. How many of us are there upstairs, roundabout, who need to walk out? The sack has enough samples cut from execution victims to make Hands of Glory for everyone—walk right past the lurkers in the forest. If someone goes and gets them right now. As for the bomb… "

I'm still thinking about the bomb as Sergeant Howe wordlessly ducks into the airlock and I hear the hiss of depressurisation. Ticking, ticking. The bomb's booby-trapped. I need to figure out a way of reaching through the case, reaching past the wires and the polystyrene foam spacers around the plutonium rod, past the surrounding parcels of lithium deuteride wrapped in depleted uranium, through the steel casing of the A-bomb trigger-

Alan is standing in front of me, leaning in my face. "Bob."

"Yeah." The basilisk gun is the solution. I think…

"Hand of Glory. Tell me what the hell I need to know."

"A Hand of Glory is fabricated from the hand and wrist of someone who has been wrongly executed. A fairly simple circuit is inscribed around the radius and ulna and the fingertips are ignited. What it does is a limited invocation that results in the bearer becoming invisible. In effect. There are variations, like the inversion laser—stick a phase-conjugate mirror on the base and it makes a serious mess of whatever the hand's pointed at—but the original use of the hand is as a disintermediating tool for observer/subject interactions. Or so Eugene Wigner insisted. How many people have you got?"

The airlock door is cycling: Alan crouches, gun levelled on the door. He waves me off to one side impatiently.

It's Howe. No luminous worms behind his face plate; he hefts a lumpy, misshapen sack and my basilisk gun as he steps through the door.

"Seven, plus yourself. You were saying?" Alan asks.

"Give me." I take the sack. It's like peeling potatoes, I tell myself, just like peeling potatoes. "Anyone got a roll of duct tape? And a pen? Great, now clear the fuck away and give me room to breathe." Just like peeling potatoes, strange vegetables that grow in a soil of horror, watered with blood. A lot of the original bits of folklore surrounding the Hand of Glory are just that. You don't need a candle made of human fat, horse dung, and suchlike, with a wick made of the hair of a hanged man. You don't need fingers from the fetus of a hanged pregnant woman, amputated stealthily at midnight. All you need is a bunch of hands, some wire or solder, a pen, a digital-analogue converter, a couple of programs I carry on my palmtop, and a strong stomach. Well, I can fake the stomach: just tell myself I'm peeling spuds, sticking bits of wire in Mr. Potato Head, triggering ghost echoes in a decaying neural network, feeding something arcane. Howe pushes in and insists on copying what I do; it's annoying at first, but monkeysee monkey-do gets results and between us we make short work of the sack. A couple of the hands are washouts but in twenty minutes flat I've got a shrunken bag and a row of ghastly trophies arranged on the guardroom table.

"Here," I say. Scary Spice—who has been shuffling nervously and keeping one eye on the airlock door-jumps.

"What's up?"

Howe watches with silent interest.

I hold up a hand. "Look." Thank Cthulhu for pocket soldering irons: the fingertips ignite neatly, that crypt-glow dancing around them.

Scary Spice looks confused. "Where are you? What's up?" His eyeballs are sliding around like greased marbles; he instinctively raises his gun.

"Safe that!" snaps Howe. He winks in my general direction.

"Hold out your left hand, Scary," I say.

"Okay." He shuts his eyes; I shove the stump of the hand into his glove. "What the fuck is this?"

I blink and try to focus on him, but he's slipping away. It's weird; I try to track him but my eyes refuse to lock on. "What you're holding is called a Hand of Glory. While you're holding it, nobody can see you—it works on the possessors outside, too, or I wouldn't be here."

"Uh, yeah. How long's it good for?"

"How the fuck should I know?" I reply. I glance at Howe.

"Put it down now," he says. A hand appears on the table and I find I can focus on Scary again. Howe glances at me. "This is a bloody miracle," he says morosely. "Pity we didn't have it a couple of years ago in Azerbaijan." He keys his mike: "Howe to all, we've got a ticket home. Alpha, Bravo, Charlie, everyone downstairs now. Captain, you're going to want to see this too."

IT'S LIKE BEING AT SCHOOL AGAIN, SITTING ONE fucking exam after another, sure that if you don't finish the question in the set time it's going to screw your life. This exam, the fail grade is anything short of 100 percent and you get the certificate, with no appeal possible, milliseconds after you put your pen down.

I'm crouching in the basement with Alan and a thing that looks like a steel dustbin on a handcart, if steel dustbins came painted green and neatly labelled THIS WAY UP and DO NOT DROP. I will confess that I'm sweating like a pig, even in the frigid air of the redoubt, because we are now down to about fifteen minutes and if this fails we won't have time to reach the gate.

"Take five," says Alan. "You're doing really well, Bob. I mean that. You're doing really well."

"I bet you say that to all the boys," I mutter, turning the badly photocopied page of arming instructions-the pamphlet that comes with the bomb has a blue cardboard cover, like a school exercise book that's been classified top secret by mistake.

"No, really." Alan leans back against the wall. "They got away, Bob. Everyone but us. Maybe you don't think that's a big deal, but they do; they'll remember it for the rest of their lives, and even if we don't follow them they'll be drinking a toast to your memory for a long time to come."

"That's reassuring." I flip another page. I didn't know H-bombs came with user manuals and cutaway diagrams, exploded views of the initiator core. "Look, this is where the pit goes, right?" I point at the page and then at a spot about five centimetres above the base of the dustbin.

"No." Alan moves my hand right up to the top of the bomb casing. "You've got it upside down."

"Well, that's a relief," I say lightly.

"At least, I think it's upside down," he says in a worried tone of voice.

"Uh-huh." I move my finger over the diagram. "Now this is where the detonation controller goes, right?"

"Yes, that's right," he says, much more reassuringly. I give the green dustbin a hard glance.

Atom bombs aren't that complicated. Back in the late 1970s an American high school physics teacher got together with his class. They designed and built an A-bomb. The US Navy thanked them, trucked it away, added the necessary plutonium, and detonated it down on the test range. The hard bit about building an A-bomb is the plutonium, which takes a specialised nuclear reactor and a chemical reprocessing plant to manufacture and which tends to be kept behind high barbed-wire fences patrolled by guys with guns.

However, atom bombs do have one interesting trait: they go "bang" when you squeeze a sphere of plutonium using precisely detonated explosive lenses. Conventional explosives. And if those lenses don't detonate in exactly the right sequence, if you scramble them, you may get a fizzle, but you don't get a firework. It's like an egg, with a yolk (the A-bomb detonator) and a white (the fusion spark plug and other bang-amplifying widgets) inside it.

So here I am, sitting next to a rogue H-bomb with fourteen minutes to run on its clock; and when Alan passes me a magic marker I draw a big fat X on its casing, because I intend to do to this bomb exactly what Brains did to his eggs—scramble it without breaking the shell.

"How many lenses in this model?"

"Twenty. Dodecahedral layout, triangular sections. Each of 'em is a slab of RDX with a concave centre and a berylide-alloy facing pointing inward."

"Gotcha." More chalk marks. RDX is mondo nasty high explosive; its detonation speed is measured in

kilometres per second. When they blow, those explosive lenses will punch the beryllium-alloy sheet inward onto a suspended sphere of plutonium about the size of a large grapefruit or a small melon. If you blow them all within a microsecond or so, the shock wave closes around the metallic core like a giant fist, and squeezes. If they go off asymmetrically, instead of squeezing the plutonium until it goes bang, they squirt it harmlessly out the side. Well, harmlessly unless you're standing nearby. A slug of white-hot supercritical plutonium barreling out of a ruptured bomb casing at several hundred metres per second is not exactly fun for all the family. "That puts the top half of the hemisphere about—here."

"Very good. What now?"

"Fetch a chair and some books or boxes or something." I pick up the basilisk gun and begin fiddling with it. "I need to align this on the hemisphere and tape it in position."

When the beryllium-alloy sphere assembles it squishes the plutonium pit inward. Plutonium is about twice as dense as lead, and fairly soft; it's a metal, warm to the touch from alpha particle decay, and it exhibits some of the weirdest heavy-metal chemistry known to science. It exists in half a dozen crystalline forms between zero and one hundred Celsius; what it gets up to inside an imploding nuclear core is anybody's guess.

"Chair."

"Duct tape."

"What next?"

"Get me a cordless drill, a half-inch bit, and a pair of scissors."

At the core of the grapefruit there's a hollow space, and inside the hollow there's a pea-sized lump of weirdly shaped metal alloy, the design of which is a closely guarded secret. When the molten-hot compressed plutonium hits it, it vomits neutrons. And the neutrons in turn start a cascade reaction inside the plutonium; every time a plutonium nucleus is hit by a neutron it wobbles like jelly, splits in two, and emits a bunch more neutrons and a blast of gamma radiation. This happens in a unit of time called a "shake"—about a tenth of a thousandth of a millionth of a second—and every plutonium nucleus in the core will have been blasted into fragments within fifty shakes of the core shockwave hitting the initiator and triggering that initial neutron burst. (If it collapses symmetrically.) And maybe a few milliseconds later the devil will be free to dance in our universe.

Twelve minutes to go. I position the chair in front of the bomb. The back of the chair is made of plywood—a real win—so I drill holes in it at the right separation, then get Alan to hold the basilisk box while I chop strips of duct tape off the reel and bind it to the chair immediately in front of the X where I think the explosive lenses lie.

"Bingo." One chair. One basilisk gun—a box with a camcorder to either side—taped to the back of the chair. One ticking hydrogen bomb. The back of my neck itches, as if already feeling the flash of X-rays ripped from the bleeding plasma of the bomb's casing when the pit disassembles in a few scant shakes of Teller's alarm clock. "I'm powering up the gun now." The gun's sensors face the bomb through the holes I've drilled in the chair's back. I switch it on and watch the charge indicator. Damn, the cold doesn't seem to have done the batteries any good. It's still live, but close to the red RECHARGE zone.

"Okay," I say, leaning back. "One more thing to do: we have to trip the observe button."

"Yes, that seems obvious," says Alan. "Um, mind me asking why?"

"Not at all." I close my eyes, feeling as if I've just run a marathon. "The basilisk spontaneously causes about 1 percent of the carbon nuclei in the target in front of it to tunnel into silicon. With one hell of an energy release at the same time, of course."

"But plutonium isn't carbon—"

"No, but the explosive lenses are made of RDX, which is a polynitrated aromatic hydrocarbon compound. You turn 1 percent of the RDX charge into silicon and it will go bang very enthusiastically indeed. If we offset it to one side like this"—I nudge the chair a couple of centimeters—"one side of the Abomb's explosive lenses predetonate, totally out of sequence, causing a fizzle. Imagine a giant's fist, squeezing the plutonium core; now imagine he's left his thumb off the top. Molten plutonium squirts out instead of compressing around the initiator and going bang. You get a messy neutron pulse but no supercriticality excursion. Maybe explosive disassembly of the case, and a mess of radiation, but no mushroom cloud."

Alan glances at his watch. "Nine minutes. You'd better be going."

"Nine—what do you mean?"

He looks at me tiredly. "Laddie, unless there's a timer on this basilisk gadget, someone has to stay here and pull the trigger. You're a civilian, but I signed up for the Queen's shilling."

"Bullshit!" I glare at him. "You've got a wife and kids. If anyone's disposable around here it's me."

"Firstly, I seem to remember you saying you'd do whatever I said before you came along on this road trip. Secondly, you understand what's going on: you're too bloody important to leave behind. And thirdly, it's my job," he says heavily. "I'm a soldier. I'm paid to catch bullets, or neutrons. You're not. So unless you've got some kind of magic remote controller for—"

I blink rapidly. "Let me look at it again," I say.

The basilisk gun is a bunch of customised IC circuits bolted to a pair of digital camcorders. I lean closer. The good news is they have fast interfaces. The bad news-

Shit. No infrared. The TV remote control program on my palmtop won't work. I straighten up. "No," I say.

"Get the hell out of here then," says Alan. "You've got six minutes. I'm going to wait sixty seconds after you leave the room, then hit the button." He sounds very calm. "Go on, now. Unless you think losing two lives is better than losing one."

Shit. I punch the door frame twice, oblivious to the pain in my wrist.

"Go!" he yells.

Upstairs, I pause in the guardroom, about to ignite one of the two Hands of Glory that are waiting for me on the table. I wonder if I'm far enough away from the bomb. (That American scientist—Harry Dagnian, wasn't it?—who did something similar by accident in the Manhattan Project: dropped a neutron reflector on top of a weapon core during an experiment. He died a couple days later, but a guard just ten feet away wasn't affected.) There's a muffled thud that I feel through the soles of my boots; a split second later I hear a noise like a door slamming.

I hear my pulse racing erratically. I hear it, therefore I am still alive. I heard the explosion, therefore the bomb fizzled. There will be no nuclear fireball to energize the conquest dreams of the ancient evil that lurks in this pocket universe. All I have to do is pick up the Hand and walk back to the slowly evaporating gate before it closes…

A minute passes. Then I put down the Hand of Glory and wait for another minute. It's no good. My feet carry me back inside and I fasten down my faceplate, switching to my canned air supply as I head down the corridor that leads to the staircase.

At the top of the stairs I key my microphone. "Alan? Are you there?"

A momentary pause, then: "Right you are." He chuckles hoarsely. "Always knew I'd die in my own bed, laddie." Another pause. "Make sure you're buttoned up before you come downstairs. This isn't a sight most people ever get to see."