In Act 2, a Cthuwulf fortress arrives on Earth. Nagisa begriends a young girl while Iczer-One investigates the alien fortress. Iczer-One becomes trapped in subspace and Nagisa is forced to protect the young girl from the parasitic monsters. Iczer-One escapes only to face the challenge of a new enemy, her "sister" Iczer-Two!
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.
