When Detective Madison Harper arrives at a remote summer camp in Shadow Falls, Northern California, her heart breaks for Jenny, the sweet little girl last seen splashing in the lake with her friends before she vanished. Peering into the silent cabins filled with rows of neatly made beds, Madison knows this idyllic place is hiding a terrible secret.

FBI special agent Mercy Kilpatrick has been waiting her whole life for disaster to strike. A prepper since childhood, Mercy grew up living off the land — and off the grid — in rural Eagle’s Nest, Oregon. Until a shocking tragedy tore her family apart and forced her to leave home. Now a predator known as the cave man is targeting the survivalists in her hometown, murdering them in their homes, stealing huge numbers of weapons, and creating federal suspicion of a possible domestic terrorism event.

It starts with the hanging woman in the Maple Valley woods; the woman with no shoes, no car and no name. On paper it’s an obvious case of suicide - but to Officer Dean Matheson, something doesn’t add up. Then there are the other deaths, deaths that also look like suicides - but are they? The victims are all women living on the fringes of society, addicts and criminals. Who will miss them? Does anyone really care if they die? Dean Matheson is making it his business to care, even if it means he becomes a target....

Twenty years ago Emily Mills's father was murdered, and she found his body hanging in the backyard. Her younger sister, Madison, claims she was asleep in her room. Her older sister, Tara, claims she was out with friends. The tragedy drove their mother to suicide and Tara to leave town forever. The killer was caught. The case closed. Ever since, Emily and Madison have tried to forget what happened that night - until an eerily similar murder brings it all back.

When a man is shot in the head, Bree Taggert and her new partner, veteran detective Dana Romano, respond to the call. They break the news to the victim’s ex-wife and learn the estranged couple’s five-year-old daughter was supposed to have been with him. What starts as a murder investigation quickly morphs into a desperate search for a missing child. The case stirs memories of Bree’s own traumatizing childhood. To find the little girl, Bree will have to relive her own terrifying past.