Agent Maggie O'Dell believes she's responding to a threat, but instead walks into a trap. The killer's weapon is a deadly virus, virtually invisible and totally unexpected. Maggie knows dangerous minds - from hauntingly perverse child predators to cunningly twisted serial killers. Now Maggie must find clues to catch the killer - while waiting to see if the lethal strain is already multiplying in her body. With every new exposure there's the potential for an epidemic. And Maggie knows she may not live long enough to stop the nightmare scenario becoming a devastating reality.