“No!” shrieked Hingis.

“Speak then,” said Vyl.

But Hingis could not betray Tallia either. While the two soldiers held Esea, the hairy man removed her boots and socks. Her small feet were as perfectly formed as the rest of her. The drumming grew louder and Hingis felt a shocking pain in the middle of his chest.

“Well?” said Vyl.

“Keep your mouth shut, Hingis,” said Esea.

Vyl gestured to the hairy man. “Do it.”

He put the point of his sword on her little toe and glanced at Hingis. Hingis wanted to scream out the code. How could any secret, even the spell vault, matter as much as his sister? But he had sworn to protect the code; he did not speak.

The hairy man thrust. Esea screwed up her face but did not make a sound. He bent and held up her severed toe. Hingis wanted to tear the sky down on the man, and Vyl, and most of all himself.

“The code,” said Vyl, “or it’s another toe. I’ll turn her into a monstrosity like you, if I have to.”

“You wouldn’t tell me,” Esea hissed at Hingis. “Don’t you dare tell him.”

“I… can’t… bear it,” Hingis whispered.

“I’ll gladly sacrifice a few toes to protect the secret – and your honour.”

She meant it, and it proved that, despite her flaws, she was more honourable than he was. Her beauty was the only foil Hingis had to his own hideousness, and if she were mutilated protecting him, he would be doubly marred.

Vyl nodded to the hairy soldier, who removed her next toe and displayed it like a trophy. Esea tried to stifle a cry but could not. The drumming grew louder.

Hingis looked down at her bloody, maimed foot and knew Vyl would not stop with her toes. He would do exactly as he had threatened, and Hingis could not endure it.

“Well?” said Vyl.

“Shut up!” snapped Esea, her face twisted in pain.

Vyl gestured to the soldiers to move away from Hingis and approached. “The code,” he said. “Whisper it to me.”

The drumming pounded in Hingis’s ears and the pain was more than he could bear. He whispered the words and numbers he had sworn to protect with his life. And he would have, but he could not protect it at the price of Esea’s mutilation, or her life.

“You bastard!” she raged, raising her left foot. “Does my sacrifice mean nothing to you?”

“Kill her slowly,” said Vyl, grounding his staff. “He can watch.”

The soldiers were still yards away from Hingis and he saw a tiny chance. Acting on rarely used intuition, he drew more power than he had ever drawn before and cast a despairing illusion. But not at Vyl, at his serpent-shaped staff.

Vyl let out a shriek of terror as the staff became a gigantic snake, the most perfect and devastating illusion Hingis had ever created. The snake twisted in Vyl’s hand, opened a bucket-sized mouth and went for his head. He knew it was illusion but, in that moment of terror, intellect could not override instinct.

Esea spoke a reshaping command and metal shattered to Hingis’s left, embedding shards of one soldier’s sword in the throat of another and the eye of a third. She bolted, hobbling on her left foot.

The snake’s mouth closed around Vyl’s skull, the finger-length fangs sinking through bone with an audible crunch. He screamed so loudly that the remaining soldiers froze, their weapons out.

Hingis rode the illusion with all he had, knowing it would not last; maintaining it was sucking the strength out of him. Then something rose like a misty sickness from the ground – no, from some source underground. A black miasma, born from poisons leaching from the slag piles and given life by the mancery used here.

It had a kind of power and he took it. Hingis gestured towards the screaming mancer and the snake shook him by the head. It levered its fangs out, widened its jaws and enveloped Vyl’s head as if to swallow him whole. His scream was cut off; he thrashed on the ground and the snake’s smaller sets of teeth moved back and forth, dragging him in until his neck and left arm were enveloped as well. His legs kicked uselessly and his free arm flailed.

The hairy soldier let out a war cry and ran to the mancer’s aid. Vyl was grunting like a half-strangled pig, and brown muck, mixed with blood, was foaming out of the snake’s mouth. The soldier stopped, gaping. The illusion faded a little. Hingis forced it back to reality. The soldier let out a roar, ran on and took a wild hack at the snake.

There was a sickening crunch and blood fountained from its mouth, then abruptly the illusion vanished. The snake staff fell to the ground and so did Vyl, blood pouring from his upper arm, which was almost completely severed.

The hairy soldier’s mouth fell open and the tip of his sword thudded into the ground. Hingis lurched back behind the broken walls.

Vyl was moaning. “You – imbecile!” He groped for his staff with his good hand and sent a blast at the hairy soldier that hurled him backwards for twenty feet, as dead as the stones all around him.

“Kill the blonde and take the monstrosity,” Vyl gasped. The staff fell from his hand. He clamped his fingers around his upper arm, vainly trying to staunch the bleeding. “Help… me.”

Two soldiers ran to him. Another two went after Esea and the remaining two came for Hingis. The miasma coiled around his throat as if to choke him. He staggered and fell to his knees, his guts churning. Aftersickness had always been his bane, though this was unlike anything he had suffered before. There was something toxic about this place.

His hunters were approaching the outer walls. Hingis checked on his wall illusions. One was fading but the first one he’d created, when he was stronger, still held. He shifted the illusion fractionally and blurred the real wall.

Esea let out a shriek, but he could not see her and could do nothing for her. The leading soldier, a huge red-faced fellow, grinned and sprang over the illusion wall towards Hingis.

Crack! The soldier’s groin came down on the broken top of the real wall with all his weight on it, jarring the sword out of his hand. The impact must have been agonising but he stifled a cry, rolled forward onto the rubble and crawled for the sword.

Hingis heaved a heavy piece of stone off the wall and dropped it on the flat of the blade, which snapped halfway along. But it was still a deadly weapon. The soldier rose, swinging the stub at Hingis’s face. He swayed sideways. The soldier swivelled to attack; there came a second crack and he groaned and fell, his hip broken.

The other soldier, not trusting anything he saw, was probing ahead with the tip of his blade. He would soon discover what was real and what was not.

Hingis lurched down between the walls, looking for Esea, but there was no sign of her. Vyl lay on the stony ground twenty feet away, covered in blood and as white as an egg. Someone had removed his arm; it was a couple of yards off. A scar-faced soldier held the stump while a small wiry fellow tightened a bloody tourniquet with a piece of stick. The stump was still dripping blood; Hingis prayed that Vyl did not have much left in him.

The toxic aftersickness was getting worse; Hingis could not last much longer. The other soldier was clambering over the wall, five or six yards away. Hingis dug deep for the strength to cast another illusion but did not find it. He was spent.

“Esea!” he choked.

From behind the chimneys he heard gasping and the sound of metal striking stone. They’d trapped her too. His head spun and he fell against the broken wall. The rough stone drove into his ribs, driving the air out of his good lung. He slid sideways onto the rubble, breathless and unable to move. His pursuer, a swarthy fellow whose dark eyes were mere slits, loomed over him.

“By the powers, you’re a hideous little bastard,” he said disgustedly.

He struck Hingis across the head with the flat of his sword, then pressed the point of the blade against his throat until the skin broke. Hingis shrank away and the soldier grinned. Six of his top front teeth were broken off in a row.

“The little bitch is dead,” said the soldier, prodding Hingis’s mangled face.

He poked the tip of the blade between Hingis’s lips and levered his mouth open. Hingis had no hope left and, having betrayed Tallia’s secret and failed his sister, just wanted to die as quickly as possible.

“Look out!” a man shrieked.

The swarthy soldier raised his sword and whirled. A good distance away stone grated on stone, then a man cried out. The sound was cut off by a liquid thud, like a rock pulverising a melon.

“Is he…?” called a different voice.

“As a maggot! Get out, get out!”

The north side of the first chimney came apart and fell with a thunderous series of crashes onto the chimney beside it, which began to collapse as well. A scream was cut off abruptly, then the narrow gap between the chimneys filled with rubble for a good ten feet. Dust swirled up and obscured the scene.

The swarthy man ran along beside the wall for a few yards, then stopped. His shoulders drooped as he stared at the place where the gap had been, then he turned back to Hingis, baring his broken teeth.

“Guess they won’t need their shares. And maybe not Vyl either.” He prodded Hingis with the sword. “On your feet!”

It was all Hingis could do to come to his knees. The swarthy man swatted him on the side of the head again, but the poisonous aftersickness was rising, and the air in Hingis’s throat was as thick as glue. He could hear himself gasping like a stranded fish; little sparks were flashing in his eyes and his lips were tingling.

“Get up, you repulsive little swine!” The soldier kicked Hingis in the guts.

He folded over, unable to move.

“Get away from my brother!” said Esea.

Tears flooded his eyes. She was alive! She was on the wall twelve feet away, pointing a short stick at the swarthy man.

He put the blade to Hingis’s throat again. “Drop it or he dies.”

Esea tossed the reshaped stick down. But whatever it had been, it was no longer a stick. It landed at the swarthy man’s feet and exploded with a little bang, scattering burning embers in all directions. Some of them landed on his trews and stuck. He tried to brush them off, but those he touched stuck to the side of his hand. Smoke trailed up from the embers, then a little patch of red grew around each one.

The swarthy man dropped his sword and tried to grind out the sparks on his hands. They stuck together. The right leg of his trousers burst into flame. He let out a pig-like squeal, vaulted the wall and raced towards the nearest pit, trailing flame and smoke.

Hingis dragged himself upright as the man dived over the edge of the pit and disappeared. Hingis heard no splash and the smoke continued to gush up.

“What was that?” he said dully.

Esea did not want to talk about it. Up close, he could see how much it had taken out of her; her normally beautiful features were slack, her skin pallid, her eyes dull and staring.

“Had to lure them right in,” said Esea. “Didn’t have the strength to do anything from a distance. Could barely pull the mortar out of the chimney from ten feet away.” She reached out with both hands. “That snake illusion was brilliant.”

“I don’t know how I did it,” he said numbly. “It just came to me.”

“Well, it saved us. Where’s Vyl? We’ve got to put him down.”

To protect the secret code Hingis had given away. He staggered to the edge of the hill, but Vyl, escorted by the two surviving soldiers, was half a mile away, racing back to Thurkad. There was no hope of catching him.

As Hingis stood there, staring after them, guilt hit him like a landslide. How was he to tell Tallia that he had betrayed the council’s most important secret, and that Snoat would have the code to the spell vault within days? She had to be told urgently but he had no way to contact her. His stomach heaved and he threw up so violently that something tore in his belly.

Esea put an arm across his shoulders. “It’s done, and we’ve got to make the best of it.”

Hingis looked down at her three-toed foot. She was maimed now, like him, and he had allowed it. He shuddered and wrenched away.

“Hingis?” she said anxiously. Then she realised the source of his revulsion, and it crushed her. “I sacrificed my toes to keep the secret safe,” she said very quietly. “And protect you. And now my foot repulses you?”

Hingis could not speak. Her perfect beauty had made his own hideousness bearable but there was no way to say it. Her lovely face crumbled and she went utterly cold. She dragged her sock and boot on over her bloody foot and rode away.

The pain in his belly grew worse. Hingis hauled himself onto his horse and rode past the pit. The swarthy man, desperate to put the fire out, had dived too soon and landed on the broken rock surrounding the greenish water. He had dragged himself to the water’s edge, leaving a bloody trail behind him, and lay still, head and shoulders submerged, legs still burning.

The stink of burning meat was still in Hingis’s nostrils an hour later. But the foulness of his twin betrayals would be there until the day he died.