When a worker exhuming bodies from a church dies a gruesome death from a pox-like disease, Hood joins an emergency medical team to trace and chase a virulent hybrid virus. Authorities scramble to avoid a pandemic. But Rachel risks contamination, and the pursuit takes on a personal urgency.

Hood's former classmate, the renowned climatologist Richard Adams, may have suffered a breakdown. Fired from his job at an environmental think tank, Adams claims that insidious powers are sabotaging his imminent breakthrough on global warming. Only by cracking an intricate code can Hood determine whether his friend - and the world - face real danger.

After a child's kidney tumor disappears, his father credits the cure to water from a particular spring. Hood and Rachel rush to the scene to investigate - along with a horde of hopeful cancer patients. But if the water has such curative power, why does it seem to make so many people sicker?