Department Q: The Keeper of Lost Causes

In Denmark, in an unsuccessful raid against a criminal, the impulsive and stubborn Homicide Detective Carl Mørck is seriously wounded by a shot; his best friend and partner dies and the other detective becomes crippled with the bullet. When Carl is recovered, he is set aside by his chief in the Department Q, where old cases are closed and filed, to work with the responsible for the department Assad. Carl stumbles with a five year-old case of a missing person, Merete Lynggaard, who committed suicide in accordance with the investigation of an incompetent detective. Carl finds strange that someone with the intention of taking her own life brings the mentally retarded brother Uffe with her. Carl learns that Merete had given a lecture before her disappearance and he requests photos from the events. Then Assad shows the photos to Uffe that reacts to one with a man called Daniel Hale. They discover that the man lives in Sweden and when they arrive, the local police informs that Daniel died while fishing. But when they see his photo, they realize that Daniel is not the man that they are looking for but another one called Lasse. But their chief wants to abort the whole operation and close the case. Will Carl and Assad find Merete still alive?