Western France, 1989: on a picturesque lake, a weeping killer submerges the unconscious body of 20-year-old Lucie Martin, her head wrapped in a blue plastic bag. In 2003, a summer heat wave parches Lot-et-Garonne, killing trees and bushes and drying out streams, and in the scorched mud of a dried lake, a fisherman finds a skeleton with a bag over its skull. In 2011, in an elegant Paris apartment, Enzo Macleod is poring over the sixth and final cold case he promised to solve. When he finds a flaw in the original evidence however, Enzo opens a Pandora's box that not only raises old ghosts, it endangers his entire family.