A young woman walks into a tunnel alone at night. Suddenly strange trenchcoat-wearing figures melt out of the walls, surrounding her and chanting, ""Come to our world!"" Ayane Isuzu, a high school girl, emerges from the darkness and single-handedly defeats the creatures, saving the woman. Nearby, Miyu Manadzuru, another high schooler, avoids a pushy companion by ducking into an alley and flying into the sky. Ayane spots the flying girl in the night sky.
At school the next day, Ayane is revealed to be a cynical loner, known as being into technology and labeled a weirdo. Meanwhile, an inspector looking into a car accident finds one of the trenchcoat-wearing figures in a wrecked man. The figure disappears, leaving a small crystal behind.
Ayane meets with Nazo, a mysterious older man who tells her to seek out Miyu since Miyu's a Gate Keeper. Ayane also gives him a bag of crystals (what's left of the Invaders she fought) in exchange for money.
That night, Ayane invites Miyu to join her so Miy
La jeune Ayane mène une double vie : étudiante sombre et taciturne au lycée et redoutable mercenaire pour le compte d’AEGIS. Afin de lutter contre la menace grandissante des envahisseurs, elle recrute Miyu, une camarade de classe qui possède elle aussi une Gate. Mais le tandem peine à trouver son équilibre : Ayane refuse d’utiliser sa Gate et Miyu subit les sarcasmes de sa coéquipière. Pendant ce temps, la mystérieuse Ghost Girl tisse dans l’ombre les prémisses d’un complot démoniaque dans lequel Ayane est directement visée.…
