Inspector Clouseau (Peter Sellers) of the National Police (France), the French national police, is called to the country home of millionaire Benjamin Ballon (George Sanders) to investigate the murder of his chauffeur, Miguel Ostos. The chauffeur was having an affair with one of the maids, Maria Gambrelli (Elke Sommer), and attacked her in her bedroom after she broke off with him. Miguel was shot and killed in her bedroom and Maria was found with the smoking gun in her hand, but claims no knowledge of how it got there as she maintains she was knocked unconscious. All evidence points to Maria as the killer, but Clouseau is convinced of her innocence because he has developed an immediate attraction to her. Realizing Clouseau has been inadvertently assigned to a high-profile case, Commissioner Dreyfus (Herbert Lom) has him removed and personally takes charge of the investigation.