"But you're a girl" protested Yue, looking away.

"And if you tell anyone else in this camp, I'll cut out your tongue" replied Erhi.

As Erhi undressed, Yue tried to focus on the wall of the tent. But try as he might, he couldn't help but notice the pair of breasts that emerged from the tightly wound cloth wrapped around her chest.

"Feel free to look. Sabar's seen me naked more times than I can count, it doesn't bother me" said Erhi.

"But Sabar's a horse" protested Yue.

"And you're my slave. Your life is worth far less than Sabar's" replied Erhi.

Yue glanced over at Erhi as she slipped out of her trousers. He noticed that she wasn't wearing any pants. Erhi caught his gaze, forcing him to look away. Naked from head to toe, she slowly walked towards him.

"Just so we're clear. If you ever think about touching these" said Erhi, pointing to her chest "or this" pointing to her crotch "or using this" continued Erhi, grabbing Yue by the balls "then I'll chop your manhood off and stuff it in your mouth. Do you understand?"

Yue nodded, his eyes watering from the pressure that Erhi was applying with her hand.

"Well I'm glad we've cleared that up" said Erhi, releasing him.

Yue checked himself to make sure that he was still intact and did everything in his power to not look at Erhi's naked backside. But despite the threat hanging over his private parts Yue sneaked a peak. Having spent the past six months living in a railway workers camp in Uzbekistan, girls were something of a novelty. Yue gasped. Erhi's back was criss-crossed with scars, thick red welts that would never fully heal.

"I told you not to look" said Erhi, putting on a silk robe.

"Who did that to you?" asked Yue, aghast.

"That story is for another time. What I want to know, is what a boy from Zhongdu has to do with that....that...thing?" asked Erhi.

"I'll tell you if you untie my hands" replied Yue.

"Slaves aren't normally the ones who make the demands you know" said Erhi.

Yue held out his hands and Erhi took out her knife. She cut through the rope but not before holding the blade to his throat to remind him to behave.

"First things first, I'm from Beijing not Zhongdu" said Yue.

'I know, you told me earlier. The Jin changed the name of their capital city, so what?" replied Erhi.

"Where I'm from Zhongdu is history, ancient history" said Yue.

"And where is that exactly?" asked Erhi.

"The future" said Yue.

"The future? What's the future?" asked Erhi.

"On the other side of that portal it's summertime in the Year of the Rat, eight hundred years from now" said Yue.

"And why should I believe you?" said Erhi.

"That night when I first saw you, you were lying on a snowdrift. You looked up at me, then a train cut across our path. How do you explain that?' asked Yue.

"A train? Is that your name for that demon? asked Erhi.

"It's not a demon, it's made from iron, it's made by man. Where I'm from people don't ride horses anymore, they ride trains. My father builds the tracks that they ride on" said Yue.

"Could you make one?" asked Erhi.

"Me? Build a train? No more than you could. But that's not important. What's important is that I have to get back to my time. I don't belong here. The longer I stay, who knows what might happen. I could have already changed the course of history just by meeting you" said Yue.

"Let you go? Are you mad? You're my slave, a gift sent by Tengri. Don't you see? With your knowledge you can help us win. You're the most powerful weapon in this whole camp" said Erhi.

"Weapon? I'm not a...."

"Shhh" said Erhi, clasping a hand over Yue's mouth.

There was a rustle from outside of the tent. Erhi picked up her knife and stole over to the entrance. She opened the flap and peered outside. A bitter chill blasted through the open canvas, but Erhi seemed impervious to the cold. Barefoot, she padded out onto the snow and made her way around the perimeter of the tent, disappearing from view. Yue found himself holding his breath. He didn't let it out again until Erhi appeared back at the entrance. She entered the tent and closed the flap behind her, stamping up and down to warm up her feet.

"From now on we have to be more careful. There is another in the camp who knows about that thing, that portal. He's a dangerous man, no doubt he will try something before we reach Samarkand" said Erhi.

"Samarkand? But I already told you, I have to go back, I don't belong here" said Yue.

"What you want doesn't matter. Tomorrow we break camp and you're coming with me. You can either walk like a man or I'll tie you up and drag you behind Sabar like dog. I don't much care either way" said Erhi.

Yue seldom dwelt on the past. Experience had taught him that it was a bad habit, but right now he was regretting his decision to run away from home. For once in his life, he should have listened to his father.