This is the first episode in the Bunny Island Series, featuring Ōkunoshima (大久野島), a small island located in the Inland Sea of Japan in the city of Takehara, Hiroshima Prefecture. It is often called Usagi Jima (ウサギ島, "Rabbit Island") because of the numerous feral rabbits that roam the island; they are rather tame and will approach humans.