An alcoholic inventor meets a princess, who impresses a snobbish woman so that his daughter can marry her son.
Drunk Sam Bisbee (W. C. Fields) takes off his shoes before entering the house, using a device to get the key in the hole; but his wife Abigail Bisbee (Louise Carter) is waiting and criticizes him. Their daughter Pauline Bisbee (Joan Marsh) kisses Bob Murchison (Buster Crabbe) good-night but won't elope with him. Optician Sam demonstrates the murder chair for robbers and the puncture-proof tire he invented. Sam gets a letter from a tire company to demonstrate his tire. Mrs. Murchison (Kathleen Howard) calls on Abigail and rejects their family until Abigail says that she is a Warren from Virginia. Sam rolls his tire through town and shows Mrs. Murchison his family pictures, causing her to threaten to disinherit Bob.
Sam drives to the tire company and parks in a no-parking zone. Police move his car. He demonstrates his tires but shoots the tires of a police car that go flat. Pauline tells Bob she has too much pride to marry him. On a train Sam writes a suicide note to Pauline and tries to take poison; but he sees a cemetery and changes his mind. Princess Marie Lescaboura (Adrienne Ames) regrets she has to marry a prince. Sam warns her not to kill herself and tells her of his daughter, saying he needs a fairy princess. Sam missed his stop and has to walk back. Gossips tell of Sam with a woman, and rumors spread. Sam is shunned and drinks roach exterminator.
Princess Marie arrives as an honored guest and asks to see Sam because he saved her life. Sam buys an ostrich to take home. The motorcade picks him up and takes him home. Princess Marie meets Abigail and Pauline and says that Sam is a hero. Abigail faints but invites them in. The mayor gives Sam a bottle in his car. Mrs. Murchison caters a party at the Bisbee house. Princess Marie meets Bob, who hopes to marry Pauline. Mrs. Murchison announces their engagement. Princess Marie asks to see Sam play golf, but he has never played before. Sam prepares to tee off but is distracted by various clubs, noisy paper, the caddie's squeaky shoes, and a pie. The president of the tire company arrives, says they tested the tires, and offers Sam money. The princess bids him up to a million dollars plus royalties. In the final scene Sam says good-bye to Princess Marie and whispers they really put over the princess stuff. She replies, "You're telling me."
The antics of W. C. Fields offer comic relief as the snobbery of wealth and class is satirized using the artificial respect for a princess as a device.