Kai Nagisa, a normal high school girl who wishes to one day become a professional wrestler, is suddenly approached by a robot known as an Iczel. Iczel urges her to help save the Earth from invading aliens called Geas. The Geas, led by Chaos and Cross, are bent on stripping Earth's resources and then destroying it. To fight the invaders, Nagisa must merge with Iczel and become a battle-suited warrior named "Iczelion". She is reluctant to take up this sudden unbelievable task and fight with the other Iczelions of Earth because Nagisa just wants to live a normal life without having such big responsibilities. Nagisa must overcome her fears and fight, together with other Iczelions, to prevent the invading alien forces from destroying their homeplanet, Earth.