Back in the past, interdimensional gates emerged on our planet, unleashing beings from five dimensions at war onto Earth. But now, a cease-fire has formed between the Z/X and humanity, with some people forging alliances with the interdimensional entities. A simple choice confronts Azumi Kakamigahara - align with the gorgeous Z/X, Rigel, or succumb to the illness that has rendered her comatose for much of her life. Little does Azumi realize that her selection involves relocating to a hidden Academy, where groups of young women and their Z/X partners are surreptitiously honing their skills to counter the imminent wave of hostile invaders. As Azumi joins forces with her newfound companions, their school falls under attack from the enemy.