Kenichi who is tired of playing as a child, asks Hattori to become an adult for just one day. With the help of Hattori, Kenichi borrows his father's clothes and disguises himself, sneaks out of the house, goes out into town, and takes a peek at the adult playground.
ママにおこづかいの値上げをしてもらおうとあの手この手で交渉するケン一だが、なかなか上げてもらえない。諦めきれないケン一は買い物へ出掛けたママのへそくりを探していると、そこへ財布を忘れたママが家に戻ってきてしまい…。
