In the late 22nd century, humans have colonized Mars, and also set up a few colonies in Jupiter's orbit. However, as time passed, the inhabitants of the Earth started to treat the space colonists, whom they called "Enders", with suspicion, subjecting them to harsh laws and repercussions. Eventually, some of the colonists founded rebel organizations, armed with particularly powerful mechas called Orbital Frames.

A young colonist from Jupiter, Leo Stenbuck, unexpectedly comes into contact with an Orbital Frame named Jehuty. A terrible power is in his hands - will he use it for good, or for evil?..