When a deadly virus surfaces in the small, wealthy town of Hidden Valley, British Columbia, Dr. Kate Morrison and Sergeant Andy Wyles work together to uncover the source of the outbreak. As the two women navigate their new relationship, Kate and Andy are also forced to navigate a highly political and increasingly panicked community. Still bearing the scars of her recent abduction, Kate is driven to discover how this virus attacks her critically ill patients while Andy investigates suspicions of bioterrorism. As the death count rises, Kate struggles with a crushing sense of helplessness, the pressure to keep the residents of Hidden Valley alive, and Andy’s growing concern that maybe Kate hasn’t yet dealt with her troubled past.