Reggie (Earl of) Havershot, twenty-eight, ugly, boxing blue at Cambridge, goes to Hollywood to rescue his cousin Egremont (Eggy), a souse, and bring him back unmarried. Reggie had been engaged once to Ann Bannister, an American newspaper girl. He finds that she is now engaged to Eggy and has a job looking after Joey Cooley, child film-star with golden curls, idol of American motherhood, pride of the Brinkmeyer-Magnifico Motion Picture Corp. T. P. Brinkmeyer is a simple, globular multi-millionaire who is bossed by his sister, Beulah, and wishes he was back in the cloak and suit business. The Brinkmeyers have an English butler, Chaffinch. All the servants in the household are hoping to be star actors if they can only get a start by impressing Brinkmeyer.

Reggie meets April June, film-star, very keen to be a countess. He is just about to propose to her when his wisdom tooth gives him gyp. At the I. J. Zizzbaum/B. K. Burwash dentist's surgery, his identity passes, under gas, into the patient under gas in the next room, Joey Cooley. They wake up with swapped personalities.

Joey, now fourteen stone, six foot one inch, and a good boxer, enjoys his new-found ability to poke his former enemies (e.g. Beulah Brinkmeyer whom he chases into the swimming pool, April June and Orlando Flower and Tommy Murphy, rival film-stars) in the snoot, to eat pancakes, drink and smoke cigars. He paints the nose of a statue of T. P. Brinkmeyer red and misbehaves generally.

Reggie Havershot, now a boy with golden curls, gets a kick in the pants from April June, and she kidnaps him so that she can hit the headlines by rescuing him. Chaffinch sells Joey's tooth for $5,000. Eggy Mannering gets engaged to a girl who is an enthusiast for the Temple of the New Dawn and teetotalism. And, when the identity switch-back comes (a motorbike accident with Joey and Reggie thrown together), Reggie will make nice Ann Bannister his countess.

Wodehouse does not bother much about language and accent differences between Reggie and Joey. But he is always funny about Hollywood, and Joey must be the only boy with golden curls in all the books of whom Wodehouse approves.

Source: Richard Usborne. Plum Sauce. A P G Wodehouse Companion.