A deluge has flooded the high ground near Hanging Falls - but heavy rains aren't the only menace descending on Timber Creek. While on a scouting mission to pinpoint trail damage, officer Mattie Cobb and her K-9 partner, Robo, stumble upon a body floating at the edge of a lake. Robo catches human scent, which leads to an enigmatic forest-dweller who quickly becomes suspect number one.

With help from veterinarian Cole Walker, Mattie identifies the victim and discovers an odd religious cult whose dress and manners harken back to the 19th century. As the list of suspects grows, an unexpected visit from members of Mattie's long-lost family sheds new light on her childhood as they help her piece together details of the fateful night when she was abducted at age two.

The tangled threads of the investigation and family dynamics begin to intertwine, but darkness threatens to claim a new victim before Mattie and Robo can track down the killers.