Johann Radek (Franchot Tone) is an impoverished Parisian medical student who overhears Bill Kirby (Robert Hutton) saying that he wished somebody would murder his wealthy aunt so that he could collect the inheritance. Radek decides to kill the old lady and her maid but is surprised by an incredibly shortsighted burglar, Heurtin (Burgess Meredith). When Heurtin stumbles over the dead body he unwittingly incriminates himself and becomes the focal point of the police investigation. Inspector Maigret (Charles Laughton) has to solve one of his most infamous cases as he pursues the murderer across the rooftops and streets of Paris. As the two protagonists play a deadly game of cat and mouse, Maigret confronts his suspect in a stunning climax on top of the Eiffel Tower.