At a psychiatric hospital, former Chief Inspector Charles Dreyfus (Herbert Lom) is largely recovered from his obsession to kill the new Chief Inspector Jacques Clouseau (Peter Sellers) and is about to be released when Clouseau, arriving to speak on Dreyfus' behalf, drives Dreyfus insane again. Dreyfus promptly escapes from the asylum and once again tries to kill Clouseau by planting a bomb while the Inspector (by periodic arrangement) duels with his manservant Cato (Burt Kwouk). The bomb destroys Clouseau's apartment and injures Cato, but Clouseau himself is unharmed, being lifted from the room by an inflatable disguise. Determining a more elaborate plan is needed, Dreyfus enlists an army of criminals to his cause and kidnaps nuclear physicist Professor Hugo Fassbender (Richard Vernon) and the Professor's daughter Margo (Briony McRoberts), forcing the professor to build a "doomsday weapon" in return for his daughter's freedom.