When the renowned choir director at a monastery is murdered, Chief Inspector Armand Gamache and Jean-Guy Beauvoir of the Sûreté du Québec are called in to investigate. They learn that one of the brothers, in this life of prayer and contemplation, has been contemplating murder. As the peace of the monastery crumbles, Gamache is forced to confront some of his own demons, as well as those roaming the remote corridors.