Llian had not been to Carcharon since the Time of the Mirror and it had been bad enough then. Now it was so polluted by waste mancery that even he could sense it. They were still hundreds of yards below the tower, on the steep path, but the air felt thicker here and had a visible shimmer.

“Careful now,” he said over his shoulder to Wilm. “Unick might be watching.”

“What about Aviel?” Wilm said desperately. “Do you think she could still —”

“I don’t know, Wilm. But we can’t stop hoping.”

It was a miserable day – overcast, windy and exceedingly cold. Patches of black ice glazed the rudely cut steps.

Llian studied the sky. “Looks like snow.”

“Bit early in the year, isn’t it?”

“Not up here. We’re three thousand feet higher than Casyme, and it’s been known to snow here on Midsummer Day. I hate this place!”

Some of the worst moments of his life had occurred here. Ten years ago Rulke had held Karan prisoner in the tower and Tensor had ordered an archer to shoot her dead. Llian had been alone, isolated and in shackles, accused of betraying her to Rulke, and back then none of the allies, except for thirteen-year-old Lilis, had believed in him.

What were they getting into? Why had Karan burned those old family papers? Whatever her ancestors had done here, it must have been really bad. Had Basunez helped wake the stone the first time, more than five hundred years ago?

They reached the top. The wind was strong here, whirling powdery snow from drifts into their faces. They crept up to the tower and through the broken doors. The upper level, where Llian had once challenged Rulke to a telling competition and beaten him, was empty. The only sign Unick had been here was an empty spirit barrel with the top smashed in.

Wilm started to speak. Llian put a finger across his lips and led him down, then out into the walled yard that extended from the rear of the tower up the ridge for hundreds of yards. It looked like a rowing boat with its bow in the air and its stern weighed down by the hideous tower.

The floor of the yard was the native rock here, an intensely hard, violet-coloured gabbro. There was moss in shady places and lichen on parts of the wall, but no other plant had taken root in the accumulated dust. Carcharon was too cold and hostile to support any higher form of life. Including us, Llian thought.

He drew Wilm behind a broken wall where they could not be overlooked from the tower.

“What are we doing out here?” fretted Wilm. “We’ve got to go after Aviel.”

“This is a strange and dangerous place.”

“But you know it well. Where would Unick be holding her?”

“I don’t know. It all seems different now.”

“How can an empty tower be different?”

“That’s what bothers me.”

Llian stepped in a scatter of gravel and something went clinking across the ground. “What’s that?”

“It’s a ring,” said Wilm, handing it to him.

A thick, unusually heavy ring – a man’s ring, surely, though sized for a slender finger. “I’ve seen it before.” The outside of the ring was unmarked but on the inside Llian made out a number of glyphs in what he knew to be the Charon syllabary. “This is Maigraith’s! Rulke gave it to her, and it’s a powerful talisman. How did it come to be here?”

He slipped it on his little finger, where it fitted snugly.

“The wind is really howling,” said Wilm.

“It never stops. Only a madman would want to come here.”

Llian knew that Carcharon had been a strange, ghost-ridden place long before Basunez had bankrupted his family by building this tower. Who had been here before, and what had they done in the unexplored levels far below Basunez’s lowest basement? And did they have anything to do with the summon stone?

Suddenly everything he looked at was surrounded by a faint rainbow. Was Unick working mancery? Or was it the ring? Llian slipped it off and the coloured outlines vanished.

He put it on and was gazing around him when he noticed scratches on a tilted slab of stone, a section broken off a longer block. Scratches in a hand that was very familiar to him, for he had read hundreds of pages of it, written on paper, parchment, beaten copper and even polished stone. It was Mendark’s hand, though it was hard to read on the raw stone. Llian closed his eyes and felt the marks with his fingertips, trying to work out the meaning.

A shape under his fingers made his heart race – the jagged Merdrun glyph. “These marks on the stone,” said Llian. “Mendark made them.”

The scratches weren’t fresh but neither did they look ancient; they weren’t overgrown by lichen.

“The last time Mendark was here was just before he died,” he added. “Could it be a warning?”

He turned over the longer section of the slab and found more writing.

It started to rain, the wind driving it at Wilm’s face in stinging drops that were rapidly turning to sleet. Mist formed, whirled about and disappeared. He stamped his feet. Why was Llian taking so long? And where were Unick and Aviel?

He drew the black sword and practised the basic strokes, but now they were clumsy and ugly; his arm had forgotten the lessons. How could he have thought to learn sword fighting from a few scribbled notes?

“Every minute we waste —” said Wilm.

“I know,” said Llian. “But this place is a labyrinth, and I need to sort it out in my mind before we go down.” He huddled in the most sheltered corner of the yard, his lips moving.

Wilm prowled about, the black sword thrust out, ready to avenge Dajaes and spit Unick the moment he appeared. Ahead of him a doorway loomed; he had not noticed it earlier. It was stone, on heavy iron hinges, and open just enough for him to put his head through. He peered in and saw an empty room, though a foul smell lingered. Unick had been here.

Wilm slipped inside and across to the further door, which stood open, and saw stairs running up and down. He crept down, the darkness thickening with every step.

One step, two, three, four. He caught the faintest hint of citrus oil and his heart leaped. Even in this cold, the scent would not last long. Aviel could still be alive. He edged down into the gloom, reached a landing and went down another couple of steps. It was almost dark here. Now he caught a different scent – black pine, and a few steps below that, cedar oil. She must have laid a scent trail in the hope that someone would come after her.

The drumming sounded and the steps quivered underfoot, a deep, slow reverberation. He went a few more steps and his foot slipped in something thick, almost jelly-like. He sniffed it.

Blood!

Had Unick discovered the trail and killed her as coldly as he had killed Dajaes? Despair overwhelmed Wilm but he had to fight it. One little patch of blood meant nothing. She was down here and he wasn’t going to fail her.

He went down another flight, then another. It was utterly dark, dank and oppressive; he felt almost as confined as he had in the cramped tunnel into Pem-Y-Rum. The drumming was all around him now. Everything was vibrating, even the bones of his skull, and he had an unscratchable itch in his left inner ear.

A scraping sound, like a boot dragging across rough stone, was followed by a hissing breath and a stench he would never forget. The reek he had smelled when Unick had —

Wilm could not afford to go there; not now. He thrust the black sword into the dark. The dragging sound grew louder, the stench fouler and so thick that he could barely breathe. The vibration was stronger here; it felt as though the walls were moving in and out.

He was panting. Something brushed his arm and panic swelled; he was trapped, slowly suffocating. He turned round and round but could not tell which way was up and which was down. Then, in an instant, claustrophobia overwhelmed him. The walls felt as though they were moving in, the ceiling dropping on him, the air being sucked from the passage. He had to get out!

He tripped on steps that ran upwards and bolted up them, despising himself for a coward, a loser and a failure but unable to stop. After several flights he burst up into the empty room near the stone door. He stood there for a second, gasping.

“Hand over the manuscript,” said a man’s voice from outside.

“Be damned,” said Llian.

Clang – a sword glancing off stone. And Llian didn’t have a sword. He was under attack!

Llian was so preoccupied with mentally trying to recreate the labyrinthine lower levels of Carcharon that he did not realise Wilm had disappeared. The wind was rising, the sleet turning to snow and, hunched in the most sheltered corner he could find, neither did he notice the lean, cloaked figure of Jundelix Rasper, Snoat’s most reliable assassin, enter the yard.

Rasper’s short hair was thick but white; his lean face was tanned to the colour of tea. He must have been fifty though he moved like a younger man. He drew a slender knife, so sharp that it could slit a throat without its owner noticing, and crept towards Llian.

A concealed door opened on the far side of the yard and Unick slipped out, pack on his back. Llian did not notice him either; Unick was upwind. Rasper gagged, though it was inaudible over the wind.

Unick drew the stubby brass Command device and pointed it at Llian. Rasper sprang, slashing at Unick, who blasted at him. Rasper swayed aside and kicked the Command device out of Unick’s hand, then whirled and ran at Llian, trapping him in the corner.

“Hand over the manuscript.”

“Be damned,” said Llian, feeling for his blunt knife.

Unick came after him, moving in on the left as Rasper approached from the right. Llian waved his feeble weapon in front of him, cursing his own inattention. Where was Wilm? Had they already finished him?

Wilm burst out through the narrow opening of the stone door and went for Rasper, who was closest. He whirled and in a fluid movement hurled his slitting knife at Wilm’s throat. Llian let out an involuntary cry.

The black sword flashed up into the fourth basic stroke, and the ten thousand times Wilm had practised it in the past week must have ingrained the movement, for he executed it flawlessly. The flat of the blade covered his throat; the hurtling knife struck it full on and the thin blade snapped.

Wilm moved instantly into the second basic stroke. Rasper drew his sword and lunged to gut him. Wilm sidestepped, swung the black sword with all his might, and Rasper barely ducked in time as the blade cut a tonsure through his white hair. He turned and ran into the sleety snow, vanishing from sight.

Llian didn’t have time to admire Wilm’s swordplay. Unick had put the Command device back together and was pointing it at him. It was the weapon with which he had killed Dajaes.

“Die, you bastard!” he said thickly.

But before he could fire, Wilm thrust his sword out in the sixth basic stroke and it pierced through the back of Unick’s thigh to the bone. He howled and flailed around, dislodging the dark crystal at the front of the Command device. His pack fell off, landed on a block of stone, and the Identity device broke apart. The Origin device skidded across the stone-surfaced yard, caught on a projection and the tubes separated, exposing the device’s innards.

Unick, blood pouring down the back of his thigh, hopped after the Origin device. Wilm stood over it and swung the sword back.

“This blade can cut rock,” he said softly. “It’ll chop you in half like a lump of suet.”

He leaped at Unick, clearly intending to avenge Dajaes. The drumming became a shuddering roar, though for once it did not affect Llian.

Unick’s fists balled like small melons. He had recently lost the little finger of his left hand, for the stump was scabbed and oozing blood. He let out a screech; he was going into one of his berserker furies and Llian did not see how Wilm could deal with it.

Llian ran three steps and swung the heavy manuscript bag by its strap at Unick’s head. It slammed into his right ear, knocking him off his feet, and when he tried to get up his right leg refused to cooperate. He looked down at the blood, shook his head as if he could not believe this was happening to him, then ran in a scuttling limp up the yard and in through the stone door.

“Well done!” said Llian. “Yet again you’ve saved my life.”

Wilm was shaking but managed a wobbly smile. “I can’t believe I did that.”

He lifted the Origin device, which looked remarkably heavy. Its brass tubes had separated, revealing a glass cylinder almost full of quicksilver. Wilm thrust it into his pack.

“Believe it,” said Llian. “Keep watch while I take a look at this.”

He picked up the Command device and put the dark crystal back in its socket. The drumming sounded, soft but compelling. Could he destroy the summon stone with the device? Yes, he could. He must! Now!

“Come on,” cried Llian. “We’re going down to the stone. I know the way now.”

“Are… you sure?”

Fury flared. “How dare you question me!” Llian swung the device towards Wilm. “Are you with me or…?”

Wilm froze, his eyes searching Llian’s face. Llian felt a momentary unease but the drumming sounded again, overwhelming all restraint. With the Command device he could blast the wretched summon stone to dust and keep the Merdrun out for ever. He ran for the door.

No, Daddy!

Llian stopped dead. The drumming was gone and so was the compulsion. “Sulien?” She had never spoken to him mind to mind before. “Sulien, where are you? Are you all right?”

No answer, of course. He lacked the gift.

He looked around. Wilm was gaping at him and Llian realised that he was still holding the Command device, that he had threatened Wilm with it, that under the influence of the drumming he had actually imagined he could use it. He shuddered and dropped it in the snow. A burning flush made its way up his face.

“Sorry, Wilm. The drumming…”

“Yes,” said Wilm, watching him warily. “I saw.”

“I heard Sulien’s voice.” Shame crushed him; his nine-year-old daughter had far more sense than he did.

“Is she all right?”

“I couldn’t tell.” Her contacting him was troubling. Llian desperately wanted to reach her, speak to her and make sure she was all right, but he had no way of returning her call. “We’d better go after Aviel.”

“Yes,” Wilm said hoarsely.

Then Rasper reappeared out of the whirling snow, and this time he had four subordinates, all armed with swords longer than Wilm’s.