BCA Special Agent Sullivan Shale has seen his share of violence and death. He's become weathered and haunted by the harsh reality of his career yet continues on despite a crippling personal loss. But when one of the largest penitentiaries in Minnesota calls requesting an investigation into an inmate's brutal death, even his expertise is pushed to the limit. Singleton Penitentiary, located in the middle of an inhospitable swamp, has become an island amidst a torrential flood. The prisoners are silent, the staff is belligerent, and the murder committed in one of the solitary confinement cells is unimaginable. Cut off from the outside world and faced with insurmountable odds, Shale must uncover a secret stretching back half a century and race against time to save himself and perhaps all of humanity from an insidious threat, that may not be human.