In a remote Oregon biotech facility, John Cope emerges from a coma to find himself in a world he no longer recognises. His identity lost, his memory vanished, he discovers that during his long sleep the planet has been plunged into a cosmic winter triggered by a meteorite impact ten years earlier. Most of the Earth’s temperate zones have been reduced to semi-arctic wastelands. One third of the United States is a lawless tundra wilderness. Below the `Line’ – America’s unofficial northern frontier – the population is counting down to the launch of the first mission to an uninhabitable planet.

Among the country’s new scientific elite is high-flying Dr Mhairi Magnusson, a neuroscientist specialising in memory retrieval. Recruited by Zygote Investments to investigate the state of Cope’s mind, she becomes convinced that he’s being used as a human guinea pig destined to be sacrificed on the altar of science. Her only chance of rescuing him is to discover his identity, using the clues thrown up by his brain scans. But when she unearths the shocking truth, she’s confronted by an agonising choice: abandon a man condemned for the terrible crimes of his past, or risk trying to save a blueprint for the future of humanity.