The body of a shot young woman, a widow, was found in a rented house. There are all the signs of suicide: a closed door, a gun in the hand of the deceased... However, the doctor who examined the body on the spot strongly doubts this. After all, the gun is clutched in his right hand, and the wound is on the left side of his head. The Doctor reports his suspicions to Inspector Japp, who, in turn, turns to his old acquaintance, the famous detective Hercule Poirot. Japp knows: the stunning Belgian loves these kinds of riddles. Poirot also does not believe in the suicide version, especially when he finds out that fingerprints from the weapon were previously carefully erased, and a large sum of money was missing from the house. But who killed then? And Poirot begins to draw up a circle of suspects...