Famous retired detective Nick Charles (William Powell) takes his wife, Nora (Myrna Loy), and their dog, Asta, to visit Nick's parents in their small, quiet town. Determined that Nick's father respect Nick's profession, Nora urges him to find a crime to investigate, unaware that Nick's presence has already frightened spy Edgar Draque (Leon Ames) into action.
After Nora buys a painting for Nick's birthday and the artist is murdered, Nick discovers that the murder is connected to espionage.