The story opens with Bertie Wooster returning to London after a holiday in Cannes, only to discover from his valet, Jeeves, that his eccentric, newt-obsessed friend Gussie Fink-Nottle has come to the metropolis. Gussie is deeply in love with Madeline Bassett, but his chronic shyness prevents him from proposing. Jeeves devises an elaborate psychological plan, advising Gussie to attend a fancy-dress ball disguised as Mephistopheles to overcome his timidity. However, this scheme goes disastrously awry when Gussie mistakes the address, loses his money and latchkey, and spends a night fleeing a terrified cabman in scarlet tights.
Meanwhile, Bertie is summoned to his Aunt Dahlia's country estate, Brinkley Court, under threat of banishment from her household chef Anatole's peerless dinners. Upon arrival, he learns that his cousin Angela and her betrothed, Tuppy Glossop, have broken off their engagement due to an argument over a shark Angela encountered in Cannes. Believing he can easily fix both romances, Bertie takes charge. He attempts to soften Angela by insulting Tuppy, but his plan backfires completely when Angela enthusiastically agrees with every derogatory remark. Simultaneously, Tuppy is induced to refuse dinner to show his grief, which inadvertently drives the temperamental Anatole to tender his resignation after seeing his masterpieces rejected.
As the household descends into gloom over Anatole's departure, Bertie tries to help Gussie again. He decides that Gussie needs alcohol to conquer his fears, but Jeeves refuses to tamper with Gussie's orange juice. Bertie successfully spikes the drink himself, transforming the timid hermit into a remarkably confident, albeit severely inebriated, orator. On the day of the local grammar school prize-giving, Gussie delivers a wildly eccentric and insulting speech that shocks the town but delights Aunt Dahlia, while miraculously managing to propose to Madeline Bassett.
Following his eccentric success, Gussie suddenly shifts his affections to Angela as a defiant gesture, leading to a frantic pursuit by the jealous Tuppy. As various characters hide in cupboards and chase each other through the corridors, Bertie struggles to untangle the web of overlapping engagements. Through a series of explosive confrontations and romantic re-evaluations, the true couples finally find their way back to one another. The crisis is fully resolved when Anatole rescinds his notice, restoring peace and culinary excellence to Brinkley Court.
