Frederick Altamont Cornwallis Twistleton, Fifth Earl of Ickenham, better known as Uncle Fred, is back "to spread sweetness and light" wherever he goes. At the request of Lord Emsworth, Uncle Fred journeys to Blandings Castle to steal the Empress of Blandings before the ill-tempered, egg-throwing Duke of Dunstable can lay claim to her. Disguised as the eminent nerve specialist Sir Roderick Glossop, and with his distressed nephew Pongo in tow, Uncle Fred must not only steal a pig but also reunite a young couple and diagnose various members of the upper class with imaginary mental illnesses, all before his domineering wife realizes he's escaped their country estate.