Makino Tsukushi, a girl who comes from a poor family, just wants to get through her two last years at Eitoku Gakuen quietly. But once she makes herself known by standing up for her friend to the F4, the four most popular, powerful, and rich boys at the school, she gets the red card: F4’s way of a “Declaration of War.” But when she doesn’t let herself be beaten by them and is starting to fall for one of the F4, Hanazawa Rui, she starts to see that there is more than meets the eye…
Orphan`s agents pilot mysterious mecha known as Grand Cheres, and search the world for mysterious, giant disks which occasionally appear, flying at high speeds and wrecking much of the countryside, or cities, when they hit the ground. After a dying disc almost kills Hime, a Brain Powerd is born from the disc. Brain Powerds are another type of Mecha, similar to but not the same as Grand Cheres.

Hime becomes the Brain Powerd`s pilot, forming a symbiotic relationship with the living mecha and joins an International Organization dedicated to stopping Orphan, or at the very least saving humanity should Orphan succeed.