The plot centers on Dr. Hugo Z. Hackenbush, a veterinarian posing as a chief of staff at a sanitarium to help save it from financial ruin. Judy Standish, the owner of the sanitarium, desperately requires financial aid to keep the facility running and prevent it from being taken over by the wealthy but unscrupulous Mr. Morgan. With the help of her fiancé, Gil Stewart, they enlist Hackenbush, hoping his reputation will attract wealthy clients. Although Hackenbush's veterinary skills raise suspicions, his eccentric methods disarm those around him.

Meanwhile, Gil places his faith in a risky scheme to win a big horse race with his steed "Hi-Hat." Assisted by Tony, the sanitarium's assistant, and the mischievous jockey Stuffy, the group devises a plan to train Hi-Hat for victory while evading Morgan's attempts to sabotage them. Amidst chaotic events, slapstick humor ensues as Hackenbush navigates through various outlandish scenarios, resulting in comical misunderstandings. The story unfolds with a mix of zany antics, unexpected alliances, and comedic duels of wits, as the characters strive to thwart Morgan's plans and secure a brighter future for the sanitarium.