Maureen O'Sullivan plays Judy Standish, a woman whose sanitarium is about to be foreclosed upon. Standish begs for help from rich patient Emily Updike, played by the hysterically funny Maragaret Dumont. Updike agrees to save the sanitarium but demands that her favorite medical practitioner, Dr. Hugo Hackenbush (Groucho Marx), be placed in charge. Hackenbush is a horse doctor by trade. Thus begins another wacky, silly adventure with the kings of comedy, Groucho, Chico, and Harpo Marx. Chico, a racing tipster, and Harpo, a jockey, find faith in Hackenbush when they discover that the good doctor is a fraud, so the trio sets off to defeat the nasty bankers who continue to scheme for the sanitarium, while also pushing forward the incipient love affair between Standish and struggling singer Gil Stewart (Allan Jones). Also included is the horse race for which the film is named, a carnival of bathing beauties, and some very odd musical numbers.
