In the story, Peter is twelve years old and in the seventh grade, but aside from his schoolwork, Fudge is creating even more troubles! For some odd reason, Fudge has taken up a hobby in money, inventing songs about money, drawing pictures of dollar bills, and searching out ways to make money. When their family visits the Mint, the situation only gets worse as their reputation is tainted with Fudge's obsession with earning money.

Worse yet, they meet Peter's long-lost uncle's family, who are extremely strange. Howie Hatcher from Honolulu, Hawaii and his perfect daughters Flora and Fauna . They invite themselves to stay with Peter's family, and only cause more mayhem when they embarrass Peter in school, and take away their privacy. In the end, they finally leave, but also shatter Fudge when their youngest son swallows Fudge's chocolate-covered tooth.