A man is about to get married when he receives a cryptic note from another woman saying to go to the maternity hospital in Chicago to see a certain doctor. He has some obvious conclusions as to why and has two women fighting for him.

Gary Cooper and Teresa Wright star in this "thoroughly appealing romantic comedy" (Harrison's REports) about a most unusual mix-up. "Brilliantly produced and written by Nunnally Johnson and skillfully directed by Sam Wood," (The hollywood Reporter) Casanova Brown also features a fine supporting cast that includes Frank Morgan (the Wizard of Oz)! Cooper stars as Casanova Brown, a small-town professor who steals his own baby when he learns his estranged wife (Wright), who is planning to remarry, is intent on putting the child up for adoption. Cooper hides out in a hotel attempt to care for the baby, which makes for some hysterically funny shenanigans as he learns a quick lesson in diapers and formulas. As if that's not enough, while he's away playing daddy - and mommy(!) - his fiance (Anita Louise) is waiting for him at the alter!