Orphan Nello and his poor, great, quiet beast Patrasche, arrive at the end of Ouida's classic tale "A Dog of Flanders", and, as written, die. But, instead of joining the angels, as the book typically goes, the two unfortunate souls have decided to get postmortem revenge for their suffering, and lead a hellish front dedicated to destroying the world. It's now up to Bakabon, his Papa, and the rest of the wacky characters of Fujio Akatsuka's "Tensai Bakabon" to stop them and their mysterious benefactor, while making some new friends along the way.

Kazuho Anamori, ​​who had difficulty fitting in with her class, meets Miko Karakida, who suffers from heart disease, and becomes close friends with her, however, six months later, Miko dies while hospitalized. Kazuho receives a letter saying that there is something to discuss about Miko. When she goes to the address she has been called to, she finds a mysterious transfer student, Rio Ukima, waiting for her.