Doctor Jasmine Marks is going back into hell.

The Hygrometric Dehabitation Region, or the "Zone," is a growing band of rainforest on the equator, where the heat and humidity make it impossible for warm-blooded animals to survive. A human being without protection in the Zone is dead in minutes.

Twenty years ago, Marks went into the rainforest with a group of researchers led by Doctor Elaine Fell, to study the extraordinary climate and see if it could be used in agriculture. The only thing she learned was that the Zone was no place for people. There were deaths, and the programme was cut short.

Now, they're sending her back in. A plane crash, a rescue mission, a race against time and the environment to bring out the survivors. But there are things Marks's corporate masters aren't telling her. The Zone keeps its secrets, and so does Doctor Fell...