Avatak started to see the scale of this expedition, stretching off down the road. There had to be thousands of riders here, thousands of horses and attendants, and carts bristling with weapons, with javelins and stabbing spears and blades. Back in Coldland hunting parties were no more than a few men and boys, gathered together on a whim. This was more like an army assembling for war. And Avatak saw an expensive-looking pavilion, bright colours under the clear blue sky, mounted on top of what looked like a rock, a fat grey boulder. No, not a rock – it moved, slow yet oddly graceful. It was some tremendous beast.

Again he smelled smoke as the wind shifted. Heads turned to the north, and faces wore worried frowns. He suspected there were plenty of folk who would rather not be riding off with the Khan to play at hunting on this particular day. But the Khan’s whim overrode all other considerations, and the hunters began to mount their horses and carriages.

Horns sounded, and there was a cheer, noisy if unenthusiastic. The Khan’s great grey beast was the first to move. It really was like a boulder, walking on legs like cut-off tree trunks, with flapping ears and a long nose that trailed to the ground. A boy, dark, slight and skinny, rode behind its huge head, slapping the beast’s ears with a switch to make it go this way and that. The Khan himself was invisible inside the tent of silk and wool strapped to its back, but the tent tipped this way and that as the animal plodded, and Avatak could not imagine that it would be a comfortable ride. The beast was an astonishing sight, and would have been even if it had not had the most powerful man in the world in a box on its back. But Avatak had seen nothing but astonishing sights since he had been brought away from Coldland.

‘Where is Pyxeas?’

Uzzia, riding beside him, shrugged. ‘With his colleague Bolghai, I imagine. Immersed in his numbers and his theories. As happy as he ever is.’

Avatak knew that the old man was agitating to be away, to return to the west. It would be a journey back over the roof of the world, Avatak supposed, and the sooner they started the better. But meanwhile, here he was hunting with the Khan. ‘Why are we here? You and I.’

‘Because we have both been observed to fare well in the games in the palace, I with the javelin, you with the stabbing spears.’

He grunted. ‘None of those sleepy, overfed beasts we faced in the games would be a match for the great bears of Coldland.’

‘Be that as it may, you have caught the eye of the Khan’s attendants. And today we are here as the guests of Bolghai.’

‘Why?’