Inside a notorious and dangerous prison, a terrifying mystery begins to unfold when inmates start dying in brutal and unexplained ways. An unseen and deadly force appears to be hunting them, spreading fear and panic throughout the prison walls. As the body count continues to rise, rival gangs that have spent years fighting each other are forced to put aside their hatred and work together. Even the corrupt prison guards must join the desperate struggle for survival. With danger hiding around every corner, prisoners and guards alike must uncover the truth behind the invisible threat before the growing bloodshed consumes them all.