Touya has always believed he is an ordinary human, until he learns that he actually comes from Eternalia, one of several worlds beyond our own, which the story calls Earthside. The Darknoids of Nosfertia have launched an invasion of Earthside, and the realm of Heavenstia responds by sending three Animanoids, part-beast, part-human beings, to stop them. With these three allies at his side, Touya takes up the fight to protect Earthside in a fantasy action series with mecha elements.