Tengri hits her gallop and accelerates after the other horse. By the midpoint of the valley, they pass Younghusband easily. Nicolas wants to sing with elation. He delights in Tengri’s power. Her urge towards the line is as pure and uncomplicated as the pull of gravity. At the far end, Nicolas is so far ahead that he is able to take a tight course around the rock and speed back, passing Younghusband, who’s still twenty yards from the turn. Younghusband’s face is tense and grim. He knows he can’t win. He knows the maps are rightly Nicolas’s, and with them all the precious information they contain. He is a gifted horseman, his mount is decent, but Tengri is a prodigious animal. As Nicolas passes him on the home stretch, Younghusband allows his horse to drift across the line, not enough to collide with Tengri, but enough to test her composure and Nicolas’s. It is a desperate gambit. Nicolas, knowing how much is at stake, is the one who panics. He snatches at his reins. Tengri stumbles and rears. Nicolas is afraid he will be crushed. A broken pelvis in this place would amount to a death sentence. He pushes against the mane and jumps clear, lands stiffly on both feet, twists, and feels his right leg give. He falls on his side, expecting to pass out, but doesn’t. Younghusband has made the turn, reaches him, and dismounts. ‘You all right, old man?’

Nicolas feels the jarring pain as two ends of broken bone clash in his lower leg. The agony displaces his appetite for reproach. He knows Younghusband cheated. So does Younghusband. Part of Nicolas also knows that, were he in Younghusband’s position, he would have done the same. But there’s also a sense of injustice: Nicolas is suffering because of Younghusband’s machismo and hurt feelings; the Russian is paying the price for all the Englishman’s bad decisions, beginning with that misguided sortie into his tent.

‘Call my men,’ says Nicolas, through gritted teeth. The command is superfluous. They’re already racing on foot towards him.

Tengri is uninjured, but the fall has pulled her girth to one side and the saddle sits wonkily on her back. She stalks back towards Nicolas and nuzzles his hand apologetically.

‘I underestimated his pace.’ Younghusband is silhouetted against the sun. ‘But he’s skittish. Reared up from nowhere. A liability in combat. I’m happy to declare the race a draw.’

‘She’s a mare,’ says Nicolas quietly, and finally, gratefully, lapses into unconsciousness.

‘We parted there, pioneers of the East.’

When Nicolas comes to, his trouser leg is split open to the thigh. He’s broken his tibia. The swelling is enormous, but at least the bone hasn’t punctured his skin. He’ll need medical help and rest, possibly for weeks. Younghusband waves vaguely towards the south-east and says there’s a lamasery where he can be tended to in comfort. ‘I need to saddle up,’ he says. ‘It was a pleasure to meet you.’ He doesn’t offer his hand in farewell. ‘Rotten luck, old man.’