In a dystopian world ravaged by zombies, a small community has endured for generations, hidden away within the walls of an ancient convent. They call themselves the Immaculates. Bound by an uncompromising faith, they are ruled by the Bishop, who exerts absolute control over every resource and every life within the enclave. When one of their own dares to steal a life-saving medicine for her dying child, she is seized and brought before a merciless tribunal. Her sentence is final: she must face a deadly ordeal designed to measure the purity of her soul.