Three years after Vanished by the Lake, Lise and Clovis are now by another lake, in Annecy, and face the challenge of a new family life with their nine-month-old son Tom as the couple takes on a demanding new investigation.

Police officers Lise and Clovis met three years ago near a lake, while investigating the disappearance of a young teenager. Their work has taken them elsewhere, to the shores of another lake: Annecy, where they face the challenge of a new family life with their nine-month-old son Tom. As the couple takes on a demanding new investigation, Clovis gets secret calls and terrifying visions - and begins to reveal a dark side. To top it off, the corpses of two women have just been found, one right after the other. Lise and Clovis have no doubt: it must be the work of a serial killer. This reawakens painful memories for Lise, who must face her past while Clovis confronts his own demons. But the two of them will have to pull together and work as a team if they want to succeed in tracking down the killer.—Happy_Evil_Dude