Erhi was beginning to have her doubts about the benefits of owning a slave from the future. After a week of criss-crossing open steppe, pursued by the Shah's army, all that Erhi had discovered about Yue was that he liked to complain and that he didn't know anything of practical use. She'd tried to put a stop to his complaining by bartering, at great personal expense, for a knackered old horse that belonged to a dead warrior. This had worked for half a morning but then he'd begun to complain about getting saddle sores. It took all her willpower not to slit his throat. He'd probably only complain while she was doing it.

She had tried to interrogate him about the future, hoping to glean useful information on the latest weaponry and means of transportation, but it turned out that Yue only knew about the two Ps; painting and the past. She didn't care about classical Chinese landscape painting and when he told her that the Great Khan would go down in the annals of history as the mightiest general that ever lived she had shrugged. So what. Every idiot from here to Japan could tell have told you that. What she wanted to know, what would have been really useful, was if Yue could tell her what was going to happen tomorrow or the day after that. But of course he didn't have a clue.

"The Mongols had not been great chroniclers of their own success" said Yue by way of excuse. "Most of what we know about their military campaigns comes from secondary Islamic and Chinese sources" he explained. "These accounts were usually skewed and exaggerated to excuse the fact that the writers were on the losing side." Erhi had given up at that point.

She couldn't fully explain to herself why she kept him alive except something in her gut, an instinct for victory that all true Mongols had, told her that he would come in useful. So she lent him salve for his saddle sores and listened patiently as he prattled on about why an artist called Ai Wei Wei illustrated everything that was wrong with the contemporary Chinese art scene, all style and statement and no underlying emotional substance. It transpired that in the future artists didn't even paint, that art had come to mean a form of expression in any medium. If only Yue had shown the same passion for weapons as he had for art, mused Erhi, she would have been able to storm Samarkand singlehandedly.

Towards the end of the week the signal was given to halt and make ready for battle. They had drawn the Shah's army away from his cities, leaving them exposed and vulnerable. Yue assured her of victory, told her that he half-remembered the details of this particular campaign and that it definitely ended with the fall of Samarkand.

"But you don't know if I will die tomorrow" said Erhi.

"No" replied Yue.

"Or if you will die" said Erhi.

Yue shook his head.

"Victory is meaningless if you're not alive to taste it" said Erhi.

Yue nodded with what she took to be assent.

"Tomorrow you will stay at camp with the baggage and the spare horses. You'll only get in my way and get us both killed" said Erhi.

"But I want to see the battle. I've never seen one before, in real life that is" said Yue.

"You can watch it from the camp. A battle is no place for a painter" said Erhi.

She drew her knife out of her boot and handed it to him.

"You should take this just in case. You never know, we might lose" said Erhi.

Yue turned the knife over in his hand, inspecting the handle.

"Don't forget to stick them with the pointy end. And a word of warning, don't let anyone into the tent except for me. In times of war the camp can be just as dangerous as the battlefield" said Erhi.

"Aren't you afraid that I might run off?" asked Yue, jabbing at an imaginary enemy.

"And go where?" laughed Erhi.

Yue cast her a moody look and slashed at the air.

"The only thing you should be doing is praying for my survival because if I die tomorrow then I guarantee that you won't be long for this world. Now try to get some rest. Who knows, your memory might be wrong. Perhaps we all get slaughtered tomorrow. If there's one thing that my life has taught me, it's that nothing is for certain" said Erhi.

As they drifted off to sleep a pure white butterfly landed besides the entrance to their tent. It folded its wings close to its body, pressed itself against the grass, and wriggled under the canvas flap. Once inside the tent the butterfly adjusted its eyes to the gloom and silently fluttered up onto the ceiling. It looked down at the sleeping bodies, relaying the images from its head hundreds of years into the future.