He was less than four hundred yards behind her and closing fast. Aviel looked for a rock to attack him with, but the ridge was so steep that every loose rock had fallen away.

She struggled up, leaving bloody fingermarks on the stone. Now he was only a hundred yards below her, gulping noisily from a flagon. He drained it and hurled it back over his head to smash on the steps far below.

He carried a pair of little barrels in a frame on his back, and he was now close enough for Aviel to recognise them as Shand’s. They contained the raw spirit he used to fortify his sweet wines, and make his fruit liqueurs.

Had she been an apprentice mancer with command of a basic fire spell she might have turned her hunter and his barrels into a living torch that would have been visible in Tolryme town, ten miles away. How she would have watched him burn! The thought shocked her. How had her life been reduced to a single urge – kill or be killed?

Twenty yards behind now. Time for desperate measures. She took the Eureka Graveolence from her belt and removed the stopper, praying that it would hurt him as much as it hurt her. She would throw it in his face, hoping the concentrated potion would make him convulse and fall to his death. She could not be sure of hitting him from a distance; she would have to wait until the last second and pray that the potion worked quickly. If it did not, he would kill her.

He looked up and for the first time she saw his face clearly. His head was enormous, bloated and purple, his face covered in dozens of scars, some infected and oozing. His nose was a scarlet segment of cauliflower, his teeth were broken and his jaw was lopsided. But his eyes were the most horrible sight she had ever seen. The eye sockets were raw red holes, as if his eyeballs had shrunk. His eyes flicked back and forth as he tried to focus, and mucus oozed down his cheeks.

Aviel gasped and her elbow struck the rock so hard that a drop of the potion splashed across her hand. She tried to wipe it off with her other sleeve but spilled another drop on her trousers. She jammed the phial back into her belt, caught a whiff of the scent potion and threw up so violently that she sprayed the rock for yards ahead.

Pain speared through the torn muscle in her belly. Her stomach churned violently, sickeningly; her head felt hot, then icy cold. The muscles in her hand began to twitch uncontrollably, then in the leg where she had spilled the potion, and the twitching spread up and down until the only parts of her body not trembling were her head and her left arm.

Now he was ten yards below. He bared his broken teeth.

“W-w-who are y-you?” she whispered. Even her tongue was twitching now.

“Gurgito Unick, at your service.”

Now he was five yards down. Those awful eyes darted back and forth.

“W-w-w-w-why?” Aviel could not get anything else out.

Two yards down. He smelled as if he were rotting inside, and rolling shivers and shudders were passing through him from one end to the other. Why was he so determined to kill her? Was it to protect the summon stone, the precious bane whose drumming had made him what he was, yet was eating him alive?

Aviel had to try again or die. With her left hand, which had now begun to twitch, she slipped out the bung of the Eureka Graveolence phial. As he bent over her his eyes slipped out of focus and she flicked the phial, spattering drops of the scent potion across his upper lip.

The drumming sounded thunderously, shaking the ground and flaking off chips of rock, which went skidding down the sides of the ridge. Unick’s eyes opened so wide that his shrunken eyeballs protruded, then he reeled back, throwing up his arms. The weight of the barrels on his back overbalanced him and he crashed down the broken steps, landing so hard that Aviel felt sure he would have caved the back of his head in.

But she could not take advantage of his fall. Her twitching muscles were totally uncoordinated. After a minute he rolled over, almost toppling over the edge, but his luck was as good as hers was bad and another thrash took him back to the centre of a step. He sat up, staring at her blearily. Blood was streaming down the side of his head.

“What… did… you… do?” He had to force each word out.

“S-s-scent potion. I used it to f-find the summon stone.”

“Why?”

She told him about the Merdrun and their plans. Unick rubbed his head, then stared at the bloody smears on his hand. He was trembling worse than before. He wiped his hand on the seat of his pants and stood up, staring towards where the ruined tower stood. The drumming was fading.

“They’ll never get past me,” said Unick. “All the power of the summon stone will be mine.”

“Malien said never use near mancery near it. It’s got to be destroyed.” She should not have told him; he would kill her for certain now.

“And you think you can do that?” he sneered.

She did not reply. She could not speak.

“The source,” he whispered. “Oh, let it be up there.”

“W-w-what’s the matter?”

“Lost the source… after I used my devices. It’s tearing me apart.”

“What d-devices?”

He partly withdrew one from his pack – a long thin brass tube with a cluster of needle-like blue crystals in one end – then shoved it back. “Origin.”

The next, a thicker, shorter brass tube with paired red crystals at the end, was Identity. She had visualised it the first time she had been connected to him; he had used it to locate her. The final device, a stubby brass tube the size of a large beer tankard, with a single dark crystal on the end, was Command.

“What are they for?” Her tongue wasn’t twitching so badly now.

“Greater mancery than has ever been imagined. Get up!”

“C-can’t move.”

The tiny eyes flicked back and forth, focused on her again. “Why not?”

“Spilled the scent potion on myself.”

“Pathetic little fool! No one can teach themself mancery.”

If he thought she was no threat at all, it might give her a chance.

He rose, picked her up, swayed towards the edge on the left and recovered only to sway even more dangerously towards the right. The hairs stood up on the back of her neck.

“Where are you taking me?”

He rubbed his eyes and worked his thick neck back and forth, struggling to focus. He was half blind close up.

“The stone needs feeding.”

The twitching faded and she felt a splintery pain in her ankle. She cried out.

Holding her with one arm, he yanked up the leg of her trousers and stared at her swollen ankle. “Disgusting twist-foot! Should have been put down at birth.”

Aviel felt the heat moving up her throat to her face. “I didn’t ask to be born like this. But you’re a monster – and you’ve created yourself.”

He thumped her in the ribs. “You know nothing about me.”

“What did you mean, it needs feeding?”

“The drumming is also a call. The stone wants power, but first it has to feed.”

He staggered up the broken steps, lurching from side to side. Most people would have climbed on hands and knees but he seemed to have no fear. She had enough for both of them.

Finally she saw their destination ahead. The ruined, nine-sided tower, perched on the highest, steepest, most windswept and barren ridge in all Bannador. It loomed above them, unreal, deformed, the product of one man’s insane obsession.

The ridge and tower wavered before her eyes and grew solid again. She knew where she was now. This was Carcharon, a terrible place where in ages past profane experiments had been carried out by reckless men, with tragic consequences.

Was that why the summon stone was hidden here? Had it been attracted to this evil place? Or was Carcharon evil because the stone was here?

She could sense something else now. A strangeness in the air and a warping of the ground, as if the great mancery done here in ages past had corrupted even the rock from which the ridge was made. Her stomach roiled and churned.

Unick stopped suddenly, gasping for breath. His breath reeked of spirits; she was half-drunk on his foul second-hand air. Feeling was coming back to her lower limbs, though. Was there anything she could do to save herself?

Do not use mancery near it, Malien had written. Under no circumstances attempt to draw upon the power of the source – this could be catastrophic.

Unick was a deluded fool and he was going to cause a disaster. She had to stop him. This must be why she had been given her special gift. And why, after she ran away from her family, she had been taken in by Shand, the only person in Bannador who could have helped her to learn the use of her gift. And why Malien’s letters had come to her. It was meant to be.

It would be a fight to the death. A fight she had to win to keep the Merdrun out of Santhenar.

But first she had to save herself from being sacrificed.