Snatching her from the rock, Ryll bounded off, but before they’d gone far he let out a roar and threw himself to one side. Tiaan fell, breaking through the crust into grainy snow. The impact winded her. A long spear stuck, quivering, in the ground some way ahead. It had gone straight over their heads.

Tiaan scrambled to her feet. Her belly felt no better. Was this her chance to get away? She tried to run for it but the lyrinx struck her behind the knees with one leg. She went face first into the snow. Another spear shattered against the rock to her right.

Ryll ran with her, taking advantage of what cover there was. An occasional glimpse showed the racing clankers, the shooters on top frantically cranking their javelards. The spears were no longer than an infantryman’s javelin but thicker, with a head of hardened steel. Propelled by a mechanism like a giant crossbow they would destroy any living thing they hit.

The lyrinx was moving as fast as a trotting horse, the breath whistling in and out of his lungs. His grip threatened to force what remained in Tiaan’s belly out either end. She could hardly breathe. Her eyes were watering and freezing on her cheeks.

Ryll began to outpace the clankers, which were slower in this rocky country. Another spear was fired but it fell well behind. However, after a further half-hour of full-speed running, Ryll stopped and bent over, gasping. For an instant she saw panic in his eyes.

He continued, plunging down the edge of the great dome they’d been crossing for the past two days. The slope steepened below them and was scored with the paths of avalanches. The clankers had spread out, while soldiers on skis were curving round on either flank. Ryll could only go directly forward. If he turned, he must be killed. Already the clankers were drawing closer and would soon be within firing distance. There was no escape.

Tiaan considered what would happen when they killed him, as they must. If they judged her a collaborator they might execute her on the spot, or take her back to the breeding factory. She’d rather die.

They headed down the steepening slope. Ryll sprang onto one of the slides, here stripped of its snow cover, taking reckless leaps that had the snow slipping underneath his feet. A misstep at this speed and they were both dead.

Crack! A ball of rock exploded against a boulder to Tiaan’s right, peppering them with shrapnel. The lyrinx yelped, rubbing one eye with his free hand. His feet slipped on ice and he nearly went down. Tiaan shrieked.

Ryll recovered and ran harder. Another ball went over their heads, neatly taking the cap of snow off a tall boulder ahead. The lyrinx darted left, weaving among the rocks. In their cover he set her down to catch his breath. Their eyes met. She could not read his expression.

The clankers were coming down the slope in three prongs, the advance guard now speeding ahead on their skis. Only minutes left. Why did Ryll not abandon her?

Below, the slope was an obstacle course of boulders, torn-up trees and avalanche mounds, treacherous conditions that would be impossible to run through, though a few strands of undisturbed snow wound between the avalanches. There the crust would be hard enough to move on. Beyond, a gentle rise concealed what lay ahead. Down to their left it looked like a frozen river.

Another ball splintered a solitary tree ahead of them. Ryll took off with Tiaan under his left arm. This was difficult terrain for a clanker. He scooted along a ribbon of snow between the debris. They crested the rise and ahead lay a broad, winding river, iced over except for necklace beads of dark water along the centre. Beyond, Tiaan could see another snow-covered dome. There was nowhere to hide and the clankers must catch Ryll as he laboured up the slope. Wherever he went, the machines would run him down. She kept hearing Minis’s cry, Tiaan, Tiaan, why have you forsaken me?

The day was fading. Darkness could not come too soon. The lyrinx kept going. She had to admire Ryll’s courage. They went over a second rise and the expanse of the river stretched before them. With a guttural cry Ryll skidded to a stop.

Below, on the ice at the other side of the river, stood a fourth clanker and ten more soldiers, five in a curving line on either side. The loaded catapult was aimed directly at them. Suddenly the ball was not there. Something whined over their heads to embed itself behind them. A cloud of snow drifted on the breeze.

Ryll sprang onto the terminus of an avalanche. Bounding recklessly from one ice-covered boulder to the next, he let out wild roars of defiance. One false step meant the end. She could sense the thrill of peril, of him pitting his strength against them all.

He took four great leaps, one after another, skidding, claws scrabbling for a grip, teetering, steadying, the great thigh muscles driving him on. Three times Tiaan thought he was going to fall and crush her. Three times he just made it. Across the river the soldiers were frantically regrouping. With a last bound he made it down off the toe of the avalanche and raced toward the river.

Ryll almost got across. He would have, had not one of the following clankers hurtled down the slope just as recklessly, and found a clear passage to the river well downstream. Ignoring Arple’s instruction, it was already ploughing across the snow-covered ice.

Emitting a deafening war cry, Ryll ran onto the ice. The surface was slippery; wind had blown the loose snow away. The clankers were not so encumbered. They converged from four directions, blocking any escape. Making a superhuman effort, Ryll gained the middle of the ice. It was not enough. They were surrounded.

The clanker bounced and jerked on uneven ground. Their headlong passage slowed. ‘Can you still see them?’ cried Nish.

‘Just now and then,’ Irisis replied. ‘The lyrinx is weaving through the boulders. We’ll have to go round. Ah, it’s a bad place for an ambush. I can’t see the beast. There it is – it’s out the other side – it’s got her under its arm. The lyrinx is really flying now. It’s going down a track between the avalanches – too narrow for us.’

Nish was practically jumping up and down. ‘Let me see, you selfish tart!’

Irisis held him away. ‘Stop it! You’re upsetting the operator.’ She turned back to the porthole. Her voice had gone flat. ‘It’s getting away. It’s up on the avalanche, bounding from rock to rock. It’s like a mountain goat,’ she said with a trace of admiration. ‘The only chance is to get it with a spear.’

‘Our shooter is loading one now,’ said Nish. ‘I can hear the ratchet going.’ He knew the sound intimately; one of his principal jobs as artificer was to adjust and repair the javelard, which could shoot a heavy spear a third of a league. It was deadly accurate in the hands of a skilled operator, though not from a moving clanker. Especially not on uneven ground.

A bell rang in front of the operator. The clanker stopped. The sighting mechanism creaked above them. Crack! Again the clanker jerked, though not as hard as when the catapult had fired. They moved off again. It was snowing. The wind intensified, whirling the flakes about. The weather was turning bad.

‘Any luck?’ cried Nish.

‘No. We’re too late; it’s nearly to the ice …’

Her voice trailed away. Perhaps she was thinking through the consequences of failure, for them. Nish certainly was.

‘It’s on the river. The ice must be thin; I can see patches of water. Arple will never risk the clankers out there.’

‘We’ve lost,’ Nish said dully.

‘Oh!’ Irisis exclaimed. ‘Brilliant. Your father did have a trump after all. Oh, yes!’

‘What?’ he said frantically.

‘There’s another clanker coming down the far side of the river, with a squad of soldiers. He must have sent them out secretly, before the blizzard, just in case.’