The route had one climb of any significance, and the cyclist attacked it hard, initially holding his breath. He didn’t slow down at all, taking the paved road as if it were flat, rather than a 6 percent incline. He was really racing now, flying, exhilarated, when, suddenly, halfway up the hill, he couldn’t breathe and there was a sharp, stabbing pain in his chest and another in his left upper abdomen. The cyclist’s hand went to his throat as he felt his airway contract. He tried to brake, but lost control and the bike veered right, hit the slight curb, and threw the cyclist hard into a downward-sloping shoulder that was half grass, half gravel. He landed awkwardly and bumped and rolled before coming to a stop. His arms and legs were scraped and cut, but that didn’t matter because, try as he might, he couldn’t catch his breath. It was as if he had breathed out but couldn’t breathe in. On top of that, he was perspiring crazily, his heart was beating at an impossible rate, and the pain was unrelenting. The man hovered on the brink of unconsciousness, unable to get up or even move.

He had no idea how long he had been lying there, his body motionless on the outside but spiraling out of control within, like a runaway nuclear reactor. After a time—ten, thirty minutes?—he was aware of figures standing around him. Three or four people were talking at once and a hand grabbed his wrist. The man was aware that these were countrymen—he was in the United States but these people were Chinese, like him. They were part of the team. He felt his body being lifted roughly from the road and laid on a hard surface, and then a different kind of motion. The last sensation he had before finally falling unconscious was of being driven, presumably back to home base.

• • •

THE TECHNICIAN IN THE VAN switched off the GPS device. It had worked—the combined tracker and vital-signs register had sounded the alarm, and the team knew at once that number five was in distress and where he was located. He had been easy to find off the public road, and luckily no one had seen him fall or stopped to help him. The crash had taken him clear of the road and down a small embankment where he wasn’t visible to passersby. The doctor in charge had been grateful for that.

Now the subject was displaying a highly unusual assortment of signs, but nothing they hadn’t seen before. The GPS showed what speed he had been going—much too fast for that phase of the training cycle. It looked as if they were losing him, but the doctor knew a fresh batch of subjects were conveniently scheduled to arrive that very day. On the other hand, it was a shame; this one showed some promise, as he had been an athlete before getting in trouble with the law.

Within twenty minutes they had reached their destination. The van backed into a loading dock where another medical team was waiting, and they transferred the cyclist into a windowless room full of emergency medical equipment. As he lay unconscious on a gurney, one orderly cut away the man’s cycling gear while another wheeled over what resembled a dialysis machine. By the time it was hooked up, the EEG monitor showed that there was no brain function, but that was of secondary importance—they had to make sure that the heart kept working so that they could recycle the blood and figure out exactly what had gone wrong, even though they had a pretty good idea.