The sun cast bleak light and knife-edged shadows across Envoy. Brightness reduced in a viewscreen, the disk showed tiny; but it was no longer another star. The ship had passed turnover and was decelerating, backing down toward her goal.

Nansen retrieved an image and frowned at it. The optical system had obtained it an hour ago, across a distance of some two million kilometers. A large asteroid lay athwart the sky, slowly rotating. The shape was too perfect a sphere to be natural, and just half a dozen small meteor craters pocked the gray surface. Therefore they must be recent, probably under one hundred thousand years old. It was other gouges and pits that disfigured the surface, black in their depths, jumbled with debris around outlines that were not round but angular. A squared-off bluff came over the horizon as the body turned. Its top was flat, except where holes showed that something had been dug out and taken away.

"A foundation," he muttered. "This was some kind of space center. A port, I would guess, perhaps supporting communication relay towers as well, and who knows what else?"

"And everything was demolished and abandoned," said Yu as low at his side. "Why? Did it become obsolete? A technology capable of building it would scarcely have needed to salvage parts. And why do we find no signs of what replaced it?"

"Spacecraft moving about  —  Something seems to be going on at a few sites —"other asteroids, two moons of giant planets, but they were off Envoy's path. Nansen glanced at a viewscreen. The living world stood as a blue spark near the sun. "Well, we are on our way to inquire."

A voice broke in, melodious, calm, sexless, the central computer speaking. "Attention. Attention. The detector program reports a thermonuclear power plant brought to full output, driving a plasma jet. It maybe a spacecraft moving to intercept."

Yu caught her breath. Shouts, whistles, and a Magyar oath flew over the intercom. Nansen sprang from his seat. "Quiet!" he ordered. "Stand by, ready for action. We need more information."

Kilbirnie could not resist calling back, "You might show a bit of enthusiasm, skipper."

Nansen's grin was brief and tight. "I'm rather busy. We'll have time to cheer later."

Tears shone in Yu's eyes. "Oh, wonderful, wonderful," she whispered.

"No surprise," Nansen said needlessly. "They were bound to notice us." After a moment: "What is surprising is  —  No, first I have to study the parameters. Engineer Yu, please take your emergency station."

"Not an emergency, Captain. Surely we have nothing to fear. But, yes, we should be alert ... for surprises." She left the cabin. Nansen sat back down and threw questions at the computer.

Presently he reported to the crew. "Yes, it is an interception boost. She's going at nearly eleven gravities. We just picked up another acceleration farther off, which will bring a meeting, too. The first will be in about three hours.

"That's if we continue decelerating as we are. Instead, we will shut down. We'd want to anyway when we come together, and this will give us time to settle in. It won't affect the rendezvous time much, if those ships change vectors when they see what we have done, which they doubtless will."

"Eleven gravities?" Zeyd cried. "But that planet has only — what?  —  seven percent more than Earth's on the surface."

"Drugs or fluid immersion for the crews," suggested Mokoena.

"Or they are machines, or God knows what," Nansen answered. "You may all take one hour after shutdown for personal preparations, food, drink, change of clothes, whatever you need." His tone gentled. "A prayer, perhaps. Then go to your stations and make ready for duty."

He entered a command. The drive cut off. Still facing rearward, Envoy flew on at high speed, almost in a straight line. Weight inside returned to normal, decks level, bulkheads upright, walking easy.

Time sped, time crept. The crew waited at their posts — Yu and Brent in central engine control, Dayan in the nerve center of instruments, Ruszek and Kilbirnie at their boats, Mokoena in the sick bay-surgery, Zeyd and Cleland at opposite ends of a wheel diameter, poised to go wherever summoned. Sundaram had joined Nansen in the main command center. There might be a sudden need for one who could guess what was meant in an alien language, and immediate physical presence was somehow better than intercom. Words did pass through now and then, fugitive speculations, small talk, attempts at humor. They died away after a spell, and silence brimmed the ship.

She signaled on every available band, and silence replied.

"It is not to be expected that their equipment will be compatible with ours, is it?" Sundaram wondered at last.

Dayan's voice: "They jolly well know the electromagnetic spectrum. If they can't pick up any of our transmissions, and can't at least send a burst of the same kind, they're more stupid than I think is possible."

Cleland: "Maybe they're, uh, sizing us up first. We could be the f-f-first visitors they've ever had."

"We'll see," Nansen said.

Mokoena: "Will we necessarily?"

The stranger hove in optical range, maddeningly minute and blurred to begin with, then the magnified image strengthening second by second. Nansen and Sundaram strained forward, peering.

They did not need to describe what they saw. Every station had a readout screen. A long cylinder terminated aft in an accelerator lattice not unlike Envoy's, the same plasma fire blue-white to drive it onward. At the bow another meshwork formed a great, shallow bowl, pierced by a mast. The hull was dull metallic, well-nigh featureless  —  except for the second fourth of its length, counting from the bow. That section was bare ribs and stringers, open to space. It enclosed an intricate web, in which solid shapes bulked. No details came through the screening effect of the metal and the tricky light-and-shadow of vacuum.

"About one hundred meters long, apart from the drive assembly, and thirty maximum diameter, apart from that dish in front," Nansen reported. "I can't be sure, of course, but I suspect the dish is intended more for transmission than reception, if it uses radio frequencies. It must be made from a composite as strong as any of ours, to stay unwarped at the acceleration it's been through."

"The entirety seems more and more as though it is purely robotic," Sundaram ventured. "That would fit with an industrialized planetary system, and perhaps the mother world a residential park. When the dwellers became aware of us, they dispatched patrol machines to investigate."

"Too much that we have seen does not fit with that," Nansen said. "Wait. Soon we may know." The tension hurt. He willed his body to ease off, muscle by muscle.

The stranger matched velocities and terminated boost. Half a kilometer away, it hung as if motionless against the huge stars.

"Still no response," Nansen told his crew. "We — Hold!"

Magnification showed him and Sundaram the forms that climbed out of the skeleton. Instruments gave dimensions and movements. To unaided vision they would have been mere glints, but they swept swiftly nearer in a V formation.

No screen at a station gave so clear a view. "Robots, yes," Nansen said like a machine himself. "Fifteen of them. Each a cylinder, about three meters long. Four assemblies with nozzles around the circumference at the waist — jet motors, I think, probably chemical. Four landing jacks aft, or so they appear to be. . . . Claws at the ends, perhaps they double as grapnels. Four arms forward, branching and rebranching . . . yes, at the ends, what must be manipulators and assorted tools. An array projecting at the nose — a lens in it? A laser? Gleams and housings elsewhere — sensors?  —  Esperad! They are turning about . . . interior wheels, minijets?" Flame flickered. Vapor roiled, thinned, disappeared. "Yes, they are on approach, they are coming in."

The shapes drew close. The optical program tracked them and displayed the images.

"Que es? They . . . they approach aft — they touch down — induction grip like our boots? But it is — Madre de Dios, no!"

The machines were on the plasma drive lattice. They clung as wasps cling to a prey. Radiance sprang from their lenses. Metal glowed suddenly white, sparks fountained, a cable writhed loose, a thin girder parted and a second robot seized the pieces to bend them before they could fuse.

"They're attacking us," Mokoena said, stunned.

"Start the drive!" Ruszek roared. "Burn the bastards off!"

"No," Yu told them. "We have already lost too much feedback for the guide fields. We would melt the entire assembly."

"Stop, please stop," Sundaram begged. His little brown hands bounded over the keyboard before him, seeking to hit on a message that might be understood.

"Shoot their ship!" Kilbirnie yelled.

Sweat stung Nansen's eyes. "Not yet. We know nothing, nada."

Brent's voice rang: "Well, we can defend our own. Lajos, you and me go out and kill those things before they take our whole hull apart."

"By God, yes!" the mate shouted. "Tim, you're nearest the small arms locker. Bring us weapons. Selim, come help us suit up."

"I will go, too," Zeyd said.

"And I," Kilbirnie put in.

"No," Nansen decreed. "Not you two. Ruszek and Brent have the military experience. We cannot risk more." A groan escaped him. He also must stay behind.

Dayan sent him a benediction. "We know how you feel, you, our captain."

"This must be s-s-some tragic mistake," Yu gasped. "They would not  —  rational beings —"

"They are doing it," Zeyd said.

Sundaram had won back his inner balance. "I am working out a program to transmit," he said fast. "Basic mathematics, flashes for numbers up to one hundred, digital symbols for operators, operations conducted to identify them. And we will vary an amplitude, sinusoidally, parabolically, exponentially, and present a succession of prime numbers. All to show we are not automatons but conscious minds. You can begin now, at every wavelength you have. I will continue adding more."

Nansen set it up for him, without hope, What harm? Doing so took a fraction of his awareness from the destruction outside. Parts were floating free in space, bobbing off into the distance. Several robots left the work to move forward. They flitted around the after wheel and parallel to the hull, slowly, on feathery gusts of jet. Ahead of them lay turrets, bays, locks, vulnerable sensors; beyond the forward wheel stretched the mast that generated and controlled the radiation shield. If he could just bring those forces to bear  —  But they heterodyned to form a hollow shell, and the requirements of feedback made their very creation dependent on a high background count.

The mother ship waited, mute. Instruments registered its mate, speeding closer.

 A shuttle jumped from forward wheel to main hull. Sweeping about on his order, the optics gave Nansen an image of it. The shuttle reached a port and secured itself. The men aboard were cycling through, into the passage beyond. They were bound for the nearest exit to space.

He knew which that would be, and focused on it. After endlessness, while the wrecking went on aft and the scout robots advanced forward, the valve drew aside. Two spacesuited figures clambered out and took stance to peer around them. Their boots clung fast, their hands gripped firearms. More were slung at their shoulders. In the harsh sunlight, they shone like armored knights. The jetpacks on their backs were like the wings of the warrior angel Michael.

They were not symbols, though. Individually fitted suits gave recognition; burly Ruszek, slender Brent. An antenna picked up their radio speech.

"On to the drive," the second engineer said. Ardor pulsed. "Shoot on sight. Bullets. A rocket would blow one into scrap. We want them in condition to study."

"Give them a chance first," the mate growled. "Maybe when they see us they will  —  Hold! Cover me."

A robot rounded the hull, flying low alongside its great curve. Light sheened off smooth alloy, dendritic arms, watchful pseudoeyes. Still clutching his rifle, Ruszek spread his arms high and wide, a token of welcome.

The laser lens came aglare. His helmet darkened barely in time to save his sight. He leaped, tore free of the hull, floated. Metal glowed where he had been and bubbled along the slash the energy beam left.

Brent was already firing. The robot spun back from impact. The slugs tore through its plating. It gyred off, jets dead. The arms flopped.

Two more appeared. Ruszek knew better than to shoot from free fall. He twisted around, activated his motor, struck the hull, went step by gripping step to join his partner. Brent's rifle hammered.

From aft rose the other machines, a swarm across the monstrous stars. Ruszek slung his rifle and freed his rocket launcher.

Lasers flashed, seeking range. Metal seared.

"The orders for that came from the ship," said Nansen. To it: "No, you shall not kill my men."

A rocket streaked on a white trail of smoke. Its radar found a target, its warhead exploded. A rose bloomed soundlessly, spread thin, vanished. Fragments tumbled where two robots had been, winking in the sunlight.

In vacuum, the concussion had merely tossed the others a little. However, their pack dispersed. For a minute or two they drifted in several directions, as if uncertain.

Nansen had entered his command.

The robots regrouped. They moved again toward the men. Ruszek and Brent stood back to back.

A torpedo slipped from a launch bay in Envoy. Nansen sent instructions. The lean shape slewed about and jetted.

Low-yield, the nuclear blast nonetheless filled heaven with incandescence. The fireball became a luminous cloud. When that had dissipated, shards whirled red-hot and molten drops hurtled like comets gone insane.

Nansen's attention was back on his men. They had had the hull between them and the explosion, sufficient shelter; else he would first have used a counterrotator to swing his vessel around. They had not moved from their position. As he watched, Brent shot an approaching robot. Again the bullets ripped thin skin and tore circuits asunder. The machine wobbled backward. Pieces dribbled from it.

The sight was almost pathetic, because the entire band had lost purpose. Momentum bore its members past. Two of them encountered the ship, took hold with their jacks, and stood. Tools on the arm-branches plucked empty space. The rest of the robots drifted by and dwindled in view.

"Hold your fire, Al," came Ruszek's hoarse mutter. "I think we've won."

A few fragments of the slain vessel struck Envoy, not too hard, sending faint drumbeats through her air.

Nansen let out a breath. His skin prickled. He smelled his sweat, felt it on brow and in armpits, heard himself as if from afar: "Return inboard, you two. Well done."

"We'd better stay here awhile, on guard." Brent's words were a little shrill, but they throbbed.

"No hay necesidad — no need." Nansen hesitated. His thoughts hastened, he believed; it was language that had gone heavy. "At least the probability of more trouble in the near future seems slight. We destroyed the mother ship, do you know? It must have been in charge. The robots doubtless have some autonomy, but without orders, they don't. . . don't know . . . what to do. At any rate, they don't when they meet something as unheard-of as we must be."

Horror spoke from Mokoena: "You destroyed — whoever was on board?"

"They were after us," Kilbirnie snarled.

"No, the ship must have been robotic, too," Dayan said. "The wreckers were — agents, organs, corpuscles serving it. I can't believe intelligent beings would mount a senseless attack. It was most likely due to a program not written for anything like us."

Nansen's tongue began to moisten. It moved more readily. "We'll discuss this at leisure, and lay new plans," he said. "Meanwhile, Mate Ruszek, Engineer Brent, we'll not hazard you further. Come back."

"To a heroes' welcome," Kilbirnie cried.

"First I'd better blow these two here apart," Ruszek said.

"No!" Brent exclaimed. "We want them to study, dissect. The military value — lasers that powerful, that small —"

"Well, I'm God damn not going to leave them squatting on our hull unless I've put their lights out. Right, Captain?"

"Can you do that with a rifle?" Nansen asked.

"We did already."

"Don't shoot them in the same places," Brent urged. "Leave different sections intact. We need the knowledge, I tell you."

"For war?" Yu protested. "Why? I thought we are agreed this was essentially an accident."

"We are not certain of that," Nansen replied. "We'll try to find out. First, of course, we'll assess the damage and commence repair."

Sundaram stirred. "No," he said. "First we should attempt contact with the second ship. It will be here in another hour, won't it?"

"It will not," Nansen declared. "I am about to launch a second missile."

"Oh, no!" Yu screamed. "You cannot tell —"

"I can gauge probabilities," Nansen answered, "and that robot brain yonder may have learned something from what has happened. It shall not get a chance to apply the information. I hope the rest of the fleet will take that as a lesson to leave us alone."

"But, Captain —"

"I am the captain. Let any guilt fall on me. I am responsible for all of us."

Sundaram parted his lips and closed them again.

Nansen's fingers wrote a command. Another torpedo eased into space. It turned, searched, found its target, plotted its course, and spurted off. After a while, very briefly, a new star winked.

There was no further sound from the engine center. Perhaps Yu had turned her intercom off. Perhaps she wept.