Following a shootout that left his two partners respectively dead and paralyzed, Chief Detective Carl Mørck is assigned to Department Q, for unsolved and closed cases, which he run with an assistant, Assad. Although they get explicit orders to only read and sort through the cases, only a single day passes before Carl looks into the mysterious disappearance of Merete Lynggaard, a politician who vanished five years earlier from a passenger ferry. The only witness is her brain-damaged brother, who was found on the car deck, screaming at the top of his lungs. The case was put to rest as an apparent suicide. Not convinced by this explanation, and against their superiors’ orders, Carl and Assad continue investigating.