Kerokero House is the cherished playground for Keroppi and his friends. However, lately, they haven't been going there to play, and it's been left in a mess. When they finally visit Kerokero House after a long time, an old man with mysterious powers appears, transporting Keroppi and the others 30 years back in time. There, they encounter children who are working hard to build Kerokero House. Those children turn out to be none other than Keroppi and his friends' own fathers and mothers!? A heartwarming fantasy tale that blossoms with a slightly mysterious and comical parent-child friendship.