Stanley Ford (Jack Lemmon) is a newspaper cartoonist enjoying the comforts of a well-to-do and happy bachelorhood in his urban New York City town house; comforts which include his loyal and attentive valet, Charles Firbank (Terry-Thomas). Stanley's comic strip, Bash Brannigan, is a secret-agent thriller characterized by a high level of realism; no matter how outrageous the plot, Stanley will not allow Brannigan to do anything physically impossible or use gadgets that don't exist. He hires actors and sets up elaborate enactments of storylines, playing Brannigan himself, while Charles takes photographs which Stanley uses as visual references when drawing each comic strip panel.
While attending a bachelor party for his friend Tobey Rawlins (Max Showalter), Stanley becomes very drunk and marries a beautiful Italian woman (Virna Lisi) who, wearing a whipped cream bikini, had become a highlight of the party when she stepped out of a large "cake". An equally drunken judge (Sidney Blackmer) performed the impromptu wedding, and the following morning Stanley wakes up next to his naked wife. He asks his lawyer Harold Lampson (Eddie Mayehoff) to arrange a divorce, but Lampson says this is impossible without legal justification.
Stanley's new bride is cheerful, affectionate, and sexy, but she does not speak English. To learn the language, she spends time with Harold's manipulative, hen-pecking wife Edna (Claire Trevor), who speaks fluent Italian. Unfortunately, in the process, she also learns Edna's manipulative ways. Charles, who has a policy of not working for married couples, leaves, taking a new job with Rawlins, who ended up being jilted by his bride-to-be. With his valet and the associated perfect organization of his life now gone, Stanley's bathroom fills up with beauty products and lingerie; he is now kept awake at night by the portable television, which his wife constantly watches to improve her English. Her high-calorie Italian cooking causes his weight to balloon up, and she announces that her mother will be coming from Rome to live with them.
Adjusting to his marital status, Stanley changes his Bash Brannigan newspaper strip from the exploits of a daring secret agent to a domestic household comedy, The Brannigans, again drawing upon his real life. The comic strip turns Bash into a bumbling idiot and becomes wildly popular with the public. His wife continues to slowly alter Stanley's lifestyle. Increasingly irritated by the restrictions of married life, Stanley calls a meeting of his associates at his all-male health club. When Edna learns of the meeting, she telephones Mrs. Ford and arouses her suspicions about Stanley's activities. Mrs. Ford sneaks into the club to confront her husband, resulting in Stanley being banned for violating its "no women" whatsoever policy.
Stanley concocts a plot in his comic strip to kill Brannigan's wife. He drugs her with "goofballs" and buries her alive in "the goop from the gloppitta-gloppitta machine" at the construction site next to their townhouse, so that Brannigan can resume his career as a secret agent. As always, he enacts the events live before drawing the strip, again with the help of his old valet Charles. After drugging his wife during a wild cocktail party, Stanley carries her up to bed, then switches to a department-store mannequin to play out her burial in concrete.
Mrs. Ford comes to, sees the finished comic strip describing Stanley's murder plan and concludes that her husband does not love her. While Stanley sleeps, she leaves, taking nothing with her. After reading The Brannigans strip in the newspapers and recognizing that Mrs. Ford has disappeared without a trace, the district attorney and police decide that Stanley must have murdered his wife. Stanley is arrested, charged with murder, and his comic strips are used as prosecution evidence at the trial. When it appears that a conviction is likely, Stanley takes up his own defense and pleads justifiable homicide, appealing to the all-male jury's frustrations regarding their own wives and marriages. He is acquitted unanimously; the men in the courtroom applaud wildly and carry Stanley out as a hero on their shoulders, much to the consternation of the stunned women left sitting inside.
Accompanied by a joyful Charles, Stanley goes home and immediately sees that his wife has returned and is in their bedroom. His valet reminds him that killing her now would not have any legal consequences; since Stanley has already been acquitted of her murder, trying him again would constitute double jeopardy. In his time without her Stanley came to realize that he loves his wife. When he enters their bedroom he finds her naked under the covers, waiting for him. After putting her wedding ring back on her finger, they are reconciled. Charles meets Mrs. Ford's attractive mother; she has come from Rome (her daughter had run home to momma) and is in the process of settling into the Ford household. Like Charles, she has a prominent tooth gap; there is instant chemistry between them. Resigned to the inevitable, he closes the door to her room so that they can share an amorous moment alone.
Only logged in users may leave a review.