Given to Armand Gamache as a gift the first day of his new job, an intricate old map eventually leads him to the Sûreté du Québec. And there he finds four young cadets in the Sûreté academy, and a dead professor. And, with the body, a copy of the old, odd map. Everywhere Gamache turns, he sees Amelia Choquet. Amelia is more likely to be found on the other side of a police line-up. And yet she is a cadet, a protégée of the murdered professor. The focus of the investigation soon turns to Gamache himself and his mysterious relationship with Amelia, and his possible involvement in the crime. The frantic search for answers takes the investigators back to Three Pines and a stained glass window with its own horrific secrets. For both Amelia Choquet and Armand Gamache, the time has come for a great reckoning.