The Edo Period witnessed the descent of 3 enigmatic space capsules to Earth. Concerned that they could disrupt life as they knew it, humanity buried them deep underground and furnished the Kamui clan with maps pinpointing their location. Presently, one-by-one, these objects have been reactivated. The first, Tri-Zenon, a member of the Zenon Guardians, has been commandeered by Akira Kamui, his sibling Ai Kamui, and their associate, Kanna. Any extraterrestrial visitors with an ulterior motive must now confront Tri-Zenon.