Elmer Tuttle, a plumber in Paris, is enlisted by beautiful Patricia Alden to help her make her lover Tony Lagorce jealous. Tony, however, is two-timing Patricia with Nina Estrados. Elmer, with the help of his friend Julius, hopes to use the high-society contacts he’s made with Patricia to find a market for his new invention, a pistol with a range-finding light. But Elmer’s attempts to interest a military leader are mistaken for assassination attempts, and with Tony and half the male uppercrust of France challenging Elmer to duels, he is in hot water not even his plumbing skills can drain away.