Hugo Hackenbush (Groucho Marx) is a veterinarian who masquerades as a lead doctor at Standish Sanitarium to aid the wealthy patient Emily Upjohn (Margaret Dumont). In order to save the financially failing sanitarium and its beautiful owner, Judy Standish (Maureen O'Sullivan), Hackenbush, employee Tony (Chico Marx) and jockey Stuffy (Harpo Marx) must find ingenious ways to help Gil Stewart (Allan Jones) and his inept racehorse, Hi-Hat, win the big race.
Longfellow Deeds (Gary Cooper), a resident of small-town Vermont, leads a simple life until he inherits a vast fortune from a late uncle. Soon, unscrupulous lawyer John Cedar (Douglas Dumbrille) brings Deeds to New York City, where the unassuming heir is the object of much media attention. When wily reporter Babe Bennett (Jean Arthur) gains the trust and affection of Deeds, she uses her position to publish condescending articles about him -- but are her feelings for him really that shallow?
