Lotus was boiling up a pot of rice on a single gas ring that screwed into a small gas canister. She had four bowls, but to her surprise, and hurt, Li and Margaret both refused any. Instead, they hungrily devoured some of the fruit that Yongli had bought for their journey. Margaret, in turn, watched in despairing silence as Lotus and Yongli scooped rice from their bowls to their mouths with wooden chopsticks. She glanced at Li, who could not even bring himself to look. There was no point in telling them not to eat it. The damage was done. To Li and Margaret as well. But Margaret could only think of the cholera toxin genes, the cauliflower mosaic and the RXV virus particles, and God knew what else, in the genetic make-up of the small white grains. It made her feel physically sick.

They ate in a tense silence, each with their own private thoughts, and afterwards Yongli took a map he had bought and spread it out on the cot bed. He dropped the train tickets on top. “Three tickets,” he said. “The train leaves Beijing just after midnight, gets into Datong at seven fifteen tomorrow morning.” He tracked the route of the train with his finger and jabbed at the dot on the map that represented the city of Datong on the border of Shanxi province and Inner Mongolia. “You’ll have to hide up during the day while I get us some transport. We’ll leave as soon as it’s dark and drive across Inner Mongolia overnight. We should reach the Mongolian border before sunrise. I’ll drop you there, return the vehicle, and then come back to Beijing. No one will know where you’ve gone.”

Margaret looked at the map with a deep sense of foreboding. Even assuming they managed to cross the border undetected, they would have a long and difficult journey across mountainous territory to Ulaanbaatar. They had no passports, very little money, and if they succeeded in reaching their destination they would then have to try to gatecrash one of the Western embassies. It was a desperate venture. “We’ll never make it to Ulaanbaatar on foot,” she said.

Li said, “I’d thought we would catch a train.”

“Of course,” Margaret said. “Why didn’t I think of that?” And Li thought her tone carried a little more of the Margaret he had come to know and love. “And if we get stopped, without passports?”

Li shrugged. “I guess we’ll be arrested. Do you have a better idea?”

She didn’t. She glanced at Yongli. “At least let us do this ourselves, Ma Yongli. There’s no need for you to take the risk. We can get to the border on our own.”