Tatsumi, a rigid and conventional person, has recently taken up a job as a teacher on the tiny island of "Aoshima" near the Ogasawara Archipelago. However, on this island, he experiences inexplicable occurrences that defy all rational explanations. This heartwarming tale of fantasy reflects the beauty and enigma of nature itself. The question remains though, is the island's serene and tranquil blue environment welcoming Tatsumi, or is there something else afoot?