On vacation at a remote lake house, a mother and her two young daughters must fight for survival after falling into a terrifying and bizarre nightmare conceived by a psychopath.

Parent and child journey through the outskirts of society a decade after a pandemic has wiped out half the world's population. As a father struggles to protect his child, their bond—and the character of humanity—is tested.

Married couple Bob and Susan Howard decide to see a marriage counselor named Judy Small, who appears trustworthy but harbors dark and conflicted impulses.