An old map leads the former Chief of Homicide for the Sûreté du Québec Armand Gamache to places even he is afraid to go, and he finds four young cadets in the Sûreté academy, and a dead professor with a copy of the old map. One of the cadets Amelia Choquet a protégée of the murdered professor, guarded and angry. The focus of the investigation soon turns to Gamache himself and his mysterious relationship with Amelia, and his possible involvement in the crime.