When twenty-two-year-old Wynter Roth is cast out of self-contained doomsday cult New Earth, a mysterious outbreak of rapid early-onset dementia is already spreading across the nation.

As Wynter struggles to start over in a world she’s been taught to regard as evil, she finds herself face-to-face with the apocalypse she’s feared all her life, convinced she’s made a terrible mistake. Until the night her sister, still a New Earth member, shows up with a set of medical samples that holds the key to decoding the disease, and Wynter learns there’s something far more sinister at play.

Now, as the power grid fails and the country descends into chaos, Wynter must find a way to get the samples to a lab in Colorado. Uncertain who to trust, she takes up with former military man Chase Miller, who has his own reasons for wanting to get close to the samples in her possession, and to Wynter herself.