A man who has just deposited a will with a notary is run over by a car. As his overcoat bears the name and address of Emile Blondin on a label, the police go there and discover that the dead man is not Emile Blondin. But this one is soon discovered murdered. The police then became interested in Georges Blondin, the victim's brother, whose goddaughter, Juliette, was also the notary's secretary.