When the book starts out, Bertie is recuperating from a bachelor party he threw for Gussie the night before. In the prequel, Right Ho, Jeeves!, Gussie became engaged to Madeline Bassett, much to the relief of Bertie, who had inadvertently become betrothed to her himself while trying to help Gussie woo her. Haunted by the memory of being attached- even briefly- to the soppily sentimental girl, Bertie is looking forward to Gussie's wedding almost as much as the groom, as it will mean that Madeline is safely and permanently married to someone else. Relating the events of the previous evening to Jeeves, Bertie remarks that surprisingly Fink-Nottle, who is generally afflicted with paralyzing shyness, had been the life of the party, confident and assured. Speaking of Jeeves, there is a little coolness between him and Bertie, because he has been endeavoring to persuade his employer to take a world cruise, and Bertie has been steadfastly resisting the idea.
Gussie, in the meantime, reveals to Bertie the cause of his new-found confidence: it was an idea of Jeeves'. When the perpetually tongue-tied Fink-nottle asked Jeeves for help, Jeeves suggests that, when he has to speak publicly, he think of disparaging things about the people he has to talk to so that he won't be intimidated by them. This works so well for Gussie that he has started keeping a notebook of insulting and/or embarrassing things which he's thought about various people, including Sir Watkyn and Roderick Spode. The problem is, Gussie has lost the notebook. Bertie fears that it will fall into the hands of one of these men, which will result in Bassett refusing the wedding, and Spode thrashing Gussie. While he hunts for the notebook, Bertie implores Jeeves to use his connections at the Junior Ganymede Club (for butlers and valets) to dig up some dirt on Spode. Jeeves agrees, and eventually supplies him with a name which will apparently crumple the dictator wannabe- "Eulalie".
Does all this sound a little convoluted? Well, Bertie and Jeeves are just getting started. Before the book draws to a close, there will be a foot chase through through Totleigh Towers, engagements broken and reinstated, the mysterious disappearance of the cow creamer, the sudden appearance of Aunt Dahlia, a pinched policeman's helmet and an angry copper, a demoralized Gussie attempting to escape the Towers via knotted sheets, and Bertie and Jeeves becoming stranded on top of a large wardrobe. Will Gussie and Madeline make it to the altar? Will Stiffy and Stinker? Where are the cow creamer and the policeman's helmet? Will Gussie be squashed by Spode, or will the mention of the mysterious Eulalie bring down the black-shorted bully? And will Bertie, unfortunately the prime suspect in the cases of the helmet and the creamer, be quick-marched off to jail, or will Jeeves once again save the day? Well, obviously Jeeves is up to the challenge, and the methods he employs to win the day are both ingenious and hilarious.