His lordship requires an expert in human behaviour to prevent the egg-throwing Duke of Dunstable from stealing Emsworth's treasured pig, Empress of Blandings. The plot's eccentricities naturally include love and romance and, crucially, three imposters. Add to the cocktail some 'Mickey Finn's', a brace of financially embarrassed nephews and a private investigator, 'Mustard Pott'.
As the mixture boils there are shot guns in the night time - plus redoubtable Lady Constance, Emsworth's sister, who could halt a cavalry charge merely with her voice. A happy and appropriate ending is of course on the cards.