It’s 1969, and Japan is in the middle of a large economic boom. That doesn’t mean that all is well, however. Mysterious beings, called “invaders”, are infiltrating Japan at an alarming rate. Earth Defense Organization AEGIS has a secret weapon to battle the invaders — Ikusawa Izuniko, a schoolgirl who can open a dimension to another world and draw devastating supernatural powers from it. One day on a routine assignment, AEGIS sensors detect an immense Gate Power source in the area — one Ukia Shun, an estranged boy who was completely unaware of his amazing power.