A girl has been found murdered in her apartment. But who killed her and why? Through a series of flashbacks, the police investigation unfolds this murder mystery.

Trial in the Stockholm City Hall, tenth judicial department. The prosecutor claims responsibility for murder. The first witness is Mrs. Elsa Boman. The testimony turns into a flashback: Mrs. Boman comes home late after having been to the cinema. She hears the shots and then running footsteps on the stairs. She glimpsed a man who suddenly departs. Then she calls the police, who will soon be in place, noting that a young woman had been shot.—Ulf Kjell Gür