The dreary succession of randomly selected Kings of England is broken up when Auberon Quin, who cares for nothing but a good joke, is chosen. To amuse himself, he institutes elaborate costumes for the provosts of the districts of London. All are bored by the King's antics except for one earnest young man who takes the cry for regional pride seriously – Adam Wayne, the eponymous Napoleon of Notting Hill.
Although the novel is set in the future, it is, in effect, set in an alternative reality of Chesterton's own period, with no advances in technology nor changes in the class system nor attitudes. It postulates an impersonal government, not described in any detail, but apparently content to operate through a figurehead king, randomly chosen.