The Earth has been targeted for invasion by the alien Cthuwulf. A young girl, Nagisa Kano, becomes the key to Earth's defense when she is forced to become the partner of Iczer-One, a lone rebel who is battling the alien invaders.

Nayuta is a normal school girl, until she meets a young boy named Kiro trying to help his sick mother. Nayuta takes them to the hospital, but inside Kiro's mother vanishes without explanation and Kiro runs away. Later that night Kiro shows up at Nayuta's house and shows her his psychic powers, enabled by a mysterious tiara he wears.