On a remote island in Quebec, a monastery stands. The monks there are one of the last surviving groups to sing and keep alive original Gregorian chants, handed down to them from generations before. But now the outside world has affected their peaceful, self-sufficient existence.

A body is found in the abbot's garden. One of the monks has been killed, and presumably by someone within the monastery. So Chief Inspector Gamache and Inspector Beauvoir come to the island to investigate and question. They have no choice but to stay in the lonely, silent monastery until the murderer is brought to light - which soon brings to the surface their own inner turmoil...