Lord and Lady Pilkington get tricked out of their money by a con man. They later run into the swindler in a hotel - which happens to be owned by their butler - and they devise a plan to scam the con man and get both revenge and their money back.

With a title like Jack's the Boy, is it any surprise that the star of this breezy quota quickie is British music-hall favorite Jack Hulbert? The star plays the son of a celebrated Scotland Yard detective, who joins the force in hopes of following his father's footsteps. Unfortunately, Jack is something of a screw-up, and before long he has become the laughing stock of the force.

On the sidewalks of the London theater district the buskers (street performers) earn enough coins for a cheap room. Charles, who recites dramatic monologues, sees that a young pickpocket, Libby, also has a talent for dancing and adds her to his act. Harley, the theater patron who never knew Libby took his gold cigarette case, is impressed by Libby's dancing and invites her to bring Charles and the other buskers in his group to an after-the-play party. Libby comes alone. A theatrical career is launched.