Wilm slid on his back, head first down a smooth, steep slope, then slowed as it shallowed out, and the top of his head thumped into something warm and sweet-smelling. No, someone. She let out a yelp as the impact pushed her a foot across the floor and he heard the tinkle of small objects being knocked over.

“Sorry,” he said.

Wilm opened his eyes. He was at the bottom of a steep-sided pit, perhaps twenty feet deep and the same in width. He looked up at Aviel, who was sitting on the floor, cross-legged. It was hot; her feet were bare and her sleeves rolled up, and many little phials were set up in a line in front of her. The impact had knocked some over and she was picking them up and putting them back in their places, looking at him from the corners of her eyes.

He sat up and embraced her a trifle awkwardly. She clung to him for a couple of seconds, then gave a little twitch; he let go and moved away. She tucked her twisted foot out of sight under the other.

“Why didn’t you go back?” said Aviel.

“I came to find you. To help you.”

“But —”

“I had a friend,” he said haltingly. “A student I met at the scholarship test.” How meaningless the test seemed now, how silly the whole idea of becoming a chronicler. “Dajaes was her name. We rescued Llian from Snout, who was about to kill him, then Unick murdered her right in front of me, for no reason at all.”

She laid a hand on his hand. “I can’t imagine what that must be like. What you’ve been through.”

“I’ve lived a lifetime in six weeks.” A shudder racked him. “And when I realised that he was after you too…”

“How did you know?”

“After he killed Dajaes he picked up your broken scent phial – Shand dropped it – and sniffed it and said, ‘I’ll have her too.’ Though I didn’t realise it was yours until days later.”

“I made it for you – to remind you of… home. But I’d accidentally made a scent potion and when Unick smelled it, it linked him to me.”

“That was bad luck!”

“It’s the only kind I have. Unick must have realised I was a threat to the stone.”

“Why would he think that?” said Wilm.

She lowered her voice. “Because I’d read Malien’s second letter. I couldn’t contact Shand, so I had to destroy the stone.”

“That was taking a lot on yourself.”

“Malien said the world was in danger,” she said simply. “And when Unick was linked to me for those few moments, I was already working on an… um, dangerous scent potion to find the stone.”

“How did you know how to make it?”

“I’d rather not say.”

He looked around. “Where’s Unick gone?”

She gave him a sad little smile. “He planned all this, Wilm. He told me you’d left your sword behind and he was going to use it to trap you, so he could feed us both to the stone.”

“I’ve made it worse,” groaned Wilm. “I always get things wrong.”

“I… I wish you hadn’t come.” She gave him another of those enigmatic sideways looks. “But I’m so glad to see you. I’ve been so alone. Just me and him.”

“What are we going to do?”

“Escape, of course. Then I’m going to use the scent potion I’m blending to make Shand destroy the stone.” She gestured at her array of phials.

How she had changed! Her self-confidence was astonishing. “Are scent potions a kind of mancery?”

“Yes.”

“How did you know you had a gift for it?”

“Shand told me. I made one by accident years ago, and it gave him a terrible case of the runs.” She laughed.

Wilm felt a small unworthy joy at the thought, but suppressed it. Shand might be a cranky old sod, but he had treated Wilm well enough. Better than Wilm had repaid him.

“But in a way I’ve always known,” Aviel went on, thoughtfully. “Being a twist-foot, a silver-hair and a seventh sister, it’s only right that I should have a gift to balance my bad luck.”

“Is it a good idea to use mancery so close to the summon stone?”

“No. I’m planning to use it up in the tower, after we escape.”

“How?”

“The stone feeds every few hours. It forces Unick to… cut off a finger or a toe. After each time he collapses for a few minutes. That’s our chance to get out.”

“How will we know?”

“The drumming gets louder and the crimson light is really bright, and it flares in time to the drumming.”

“I wonder why it takes his fingers and toes,” said Wilm, “and not yours?”

She looked down at her foot. “Apparently I’m not corrupt enough, though the way I’m going…”

“You’ll never be like him!”

“I can feel the stone working on me. Maybe that’s where I got the idea of using a scent potion on Shand.” She went pink. “I’m so ashamed; he’s been so good to me.”

“The stone is working on me too. Only it’s got more to work on.”

Wilm felt the need to confess his folly in keeping, then losing, Unick’s Origin device.

She did not judge or criticise him. But then she never had. Aviel nodded. “We have to look out for each other, Wilm. If you see signs that the summon stone is taking me over or making me do something I shouldn’t, you’ve got to tell me.”

“All right.” It was impossible to imagine Aviel ever doing anything really bad.

“I’ve got to finish this potion now. Don’t talk to me. See if you can find a way out. We may not have long.”

Her face took on the familiar closed-off look she wore when she was working. Wilm felt pushed away, but told himself that it was just her being focused.

He studied the pit, which was smooth-walled in some places, such as where he had slid down, and slightly corrugated in others, like the back of a caterpillar. The rock consisted of alternate light and dark layers, sometimes in gentle undulations, sometimes twisted and contorted. It was very hard and there were no cracks in it, but the pale layers stood higher than the dark ones, providing small handholds.

Could he climb it? The shallowest angle was about sixty degrees. After his experience on the wall earlier, Wilm thought he might be able to manage it, and if he fell it would not be fatal. But how to get Aviel out? She could not climb such a steep slope, and neither could he carry her up it. Unick had chosen their prison well. The possibility of escape was enough to give them hope, but it surely could not be done.

Nevertheless he began. The first ten feet proved easy enough, though after that it was steeper and the handholds were shallower. It took five attempts before he made it up. He sat at the top, looking down. Aviel was carefully adding tiny amounts of one scent, then another, to a phial, shaking it then setting it down while she uncapped the next.

The drumming started. The light went from a dull brick-red to a lurid crimson and began to pulse.

“It’s feeding on him!” said Aviel, with a little shudder.

“Is the potion ready?”

“It’s way off. Can you get me out?”

She packed the phials in her belt loops. Wilm felt a momentary panic. With a length of rope or strong cord it would have been easy, but he hadn’t thought to bring any from Shand’s house.

“Have you got any spare clothes in your pack?”

“Yes… ?” she said hesitantly. “Trousers and shirt and… underwear.”

“Chuck your pack up. I’ll tie the clothes together.”

She did not move.

“It’s the only way,” said Wilm. “Hurry.”

She threw the pack up. It didn’t go high enough. She tried again with a similar result.

“Sorry,” said Aviel.

Wilm checked the passage behind him. There was no sign of Unick. He was turning back as Aviel swung her pack by the straps and gave it a mighty heave. The edge of something hard and heavy struck him across the forehead and knocked him off his feet.

“Wilm?” she cried.

He sat up, his head spinning, then crawled to the edge and looked down. Blood dripped off his forehead down the slide.

“I’m really sorry,” she said. “I didn’t mean…”

“It’s all right.”

He opened her pack and took out a pair of trousers and a shirt, and some underwear. He hastily shoved the underwear back in, tied her shirt to the legs of the trousers and tested it. It would not take his weight but it might hold hers. She had climbed as high as she could go but could still not reach his makeshift rope.

“Can I have your coat?”

She tossed it up and he tied it on. Still not long enough. He took off his sweaty blood-spotted shirt and tied it to her coat. After checking each knot, he lowered it down to her.

“Can you grip tightly enough?” he said.

“I’m not sure.”

“Make a loop in the sleeve.”

She did so, took hold of it with both hands and he began to raise her. Though she was slender and small-boned, it proved surprisingly hard work and his head was throbbing by the time she stood beside him. She flicked a glance at his bare chest and looked away hastily.

“How are we doing for time?” said Wilm, untying his shirt and putting it back on. “The drumming doesn’t sound as loud as it was.”

She stuffed her clothes into her pack. “The light isn’t as bright either. That usually means he’s rousing.”

They hurried up the passage and came to a fork. “Which way?” said Wilm.

Aviel gnawed at her lower lip. “This way… I think.” She indicated the left.

They continued. Wilm’s pulse was racing, and he felt a troubling prickling on the backs of his hands. He wanted to run but the best Aviel could manage was a fast hobble. They turned a corner and she said, “Ugh!”

“What’s the matter?”

“I can smell him. He’s coming. He’s close!”

Wilm could see the fear in her blue-grey eyes. He felt a fierce surge of protectiveness, followed by black rage. She reached out to him without realising it. He took her hand. They turned another corner and Unick stood in their path. He was dripping with rancid sweat, swaying from side to side, and a filthy flagon dangled from his right hand. Two more of his toes were gone.

“I was hoping you’d get her out,” said Unick. “Saves me the trouble.”

Whatever he had in mind, it was bound to be bad. Wilm’s fury surged. He pulled free of Aviel and, without thinking, ran at Unick.

Unick blinked at him, then smiled and began to raise the flagon. He was by far the heavier man but his reactions were dull, his movements slow. Wilm lowered his head and, running full bore, drove it into Unick’s midriff and kept going, forcing with all the strength in his legs. The impact lifted Unick off his feet and hurled him backwards several yards. His head struck the floor and he lay still.

Wilm stared at him, breathing hard. His head was throbbing again. “Is he…?”

“It would be too much to hope for,” said Aviel. “That was reckless, Wilm, but well done.”

It was his chance to avenge Dajaes. He was standing there, trying to convince himself to strangle Unick, and that it was the right and only thing to do, when the brute leaped up and bolted into the darkness.

“I should have done it,” Wilm said bitterly. “Why did I hesitate?”

“Because you’re a good man, not a cold-blooded murderer.”

“What if he kills someone else? Or lets the Merdrun in?”

“What if, by sparing his life, you’ve done the right thing?”

“Ha!”

“We can’t see the future, Wilm.”

They hurried on and shortly emerged outside the summon stone cavern. Wilm headed in.

Aviel grabbed his arm. “Every time you go near it, it’s more likely —”

“I’ve got to be armed.”

He darted in and knew that Aviel was right. The drumming was not as loud as before yet he could feel the stone trying to get at him. The black sword lay on the top, though it was in its copper scabbard this time. He lifted it off. It was blood warm. He raced back to Aviel, took her hand, and they headed up through the thick, confining darkness. He retrieved his coat.

“How long was your sword on top of the stone?” said Aviel.

“Hours.”

“What if it’s picked up something from it?”

“I have to be armed.”

“Where did you get it? I’ve never seen black metal before.”

“Neither have I.” Wilm explained where it had come from, and that it could be enchanted.

“Mendark wasn’t a very nice man,” said Aviel, her eyes searching Wilm’s.

As he hurried on, she stifled a cry. He realised that he was walking faster than she could manage.

“Would you like me to carry you?” he said without thinking.

“No!” she said sharply. She had always been fiercely independent. Her hand went round his wrist. “But thank you. You’ve done more for me than I can ever repay. Is it much further?”

“No.” He hesitated. “I should warn you that Shand isn’t happy with me at the moment.” He explained. “Ussarine is nice, though.”

He told her how everyone had ended up here and what was going on in the outside world. They went the rest of the way at a slower pace and emerged in the tower at the level of the yard. It was dark outside and still snowing gently. There must have been well over a foot of snow in the yard, for the bodies had been reduced to elongated mounds.

“What time is it?” said Aviel. “I lost track down there.”

No stars were visible; there was no way to be sure. “Maybe four in the morning.”

As they squeezed out through the door into the yard, Wilm saw a bright flare of white light up the far end, not far from the workshop.

“What was that?” said Aviel.

The light grew brighter and he made out two figures to one side, Shand and Ussarine. The light appeared to be coming from a hoop-shaped woven structure propped between blocks of stone.

“Looks like he’s trying to make the trial gate,” said Wilm.

They crept up the sloping yard, keeping to the shadows. Ussarine was on the left side of the hoop, holding it vertical.

“What do you think?” she said to Shand.

“Done as much as I can right now,” he said wearily. “We’ll get a fresh start in the morning. With luck we’ll have a working gate by dark.”

He walked across in front of the hoop, staring at it.

Suddenly the ground shook, then crimson light fountained up through the stone directly under the hoop. Ussarine yelled and leaped aside. The white light outlining the hoop went pink, then a brilliant red. Shand brandished a fist and it turned white again, but the whiteness only lasted a second before it became red once more. Then, in an instant the hoop became a gate, a whirling tunnel like the one that had taken Karan and Llian to Alcifer.

“Look out!” roared Shand.

He turned to run but the gate lifted him off his feet and sucked him through. Ussarine cried out but she could not resist its pull either. They vanished.

“Did the summon stone do that?” said Wilm.

“I’d say it opened the gate before Shand was ready, to get rid of him.”

“What do we do now?”

“We can’t break the stone by ourselves. We should go to the gate.”

“Are you sure it’s safe?”

“It can hardly be less safe than here.”

They ran hand in hand for the gate, but it turned white again, bounced them off their feet and faded away, leaving them all alone in one of the most dangerous places in the world.

“Ah!” gasped Aviel.

“What’s the matter?”

“Twisted my ankle.”

Wilm picked her up and this time she made no complaint. “We’ve got to go.”

He carried her down the yard and through the tower to the front doors of Carcharon. There he stopped, contemplating the steep and icy path. It would be incredibly dangerous in the dark; they would literally have to feel their way. But it was not as dangerous as remaining here.

“Ready?” said Wilm.

“No,” said Aviel.

“Why not?”

“Wherever Shand’s gone, I don’t think he’ll come back. He’s got Snoat’s army to deal with. It’s up to us now.”

“But you just said we can’t affect the summon stone.”

“If the Merdrun come through, it’ll be the end of the world, Wilm.”

“You’re right. It was Llian’s job to smash the stone but he’s gone. It’s up to us now.”

“We’ve got to find a way. No one else can.”