C.C. Baxter (Jack Lemmon) is a downtrodden office clerk who courts favour with the executives in his office by giving them the key to his apartment for their extramarital flings.
Among them is his callous boss, who Baxter eventually learns is using his place to sleep with Miss Kubelik (Shirley Maclaine), the sweet elevator operator he's loved from afar.
After Sheldrake coldly dumps the vulnerable young woman, she winds up in Baxter's apartment, giving the clerk the opportunity to win the woman of his dreams – but possibly lose his job.
