Bad dreams stop when you wake up...One-time doctor turned writer Clio Marsh joins a survival training course based on the Norfolk Broads as part of the research into a new novel - strictly as an observer, she thinks. But course directors Hollis and Chase have other ideas, and Clio is soon immersed in a punishing boot-camp regime for which she is sorely unprepared. Most of her fellow trainees fare little better, and within days more than one has succumbed to a mysterious illness whose symptoms closely resemble the 'marsh fever' talked of in ominous tones by the locals of Graveleigh, an isolated village at the water's edge. Graveleigh's nearest neighbour is Growth Industries, a chemical plant with a sinister reputation. When Clio and her companions seek refuge at G.I.'s headquarters after a training exercise goes badly wrong, they are treated to a less than warm welcome - and what started as a bad dream soon turns into a nightmare...