The notorious homicide detective Evert Bäckström is visited by his neighbour, the boy scout Edvin, who's made a macabre discovery; a woman's cranium with a bullethole. Who is she and how did she die? Convinced there's been a crime, Bäckström opens a murder investigation, which is immediately met with resistance. When they finally find out the identity of the woman, the investigation takes a turn. Bäckström realises that this might be the hardest murder mystery he’s ever been faced with.