 Music conductor Alex Benedict has an affair with a pianist, and when the pianist threatens to reveal their affair to Benedict s wife, whose wealthy mother owns the company on which Benedict s career is dependent, Benedict decides to permanently silence his mistress. He strangles her and arranges for her death to look like a suicide by kitchen stove gas asphyxiation. Lieutenant Columbo, a cunning detective in a rumpled raincoat, doesn t believe the pianist took her own life and suspects that Benedict was responsible for her death. He pesters Benedict with constant questions as he searches for clues to place Benedict at the murder scene.