After three years' hard time, minding no-one's business but his own, Ray Klein wins his parole. That same day, the disciplinary perfection of Green River State Penitentiary is torn apart by tribal war, and the prison falls into the hands of its inmates. As the River sucks them all towards the abyss, Klein must choose either to claim his freedom and leave the ones he cares for to die, or risk everything and fight...