The story behind is as follows. In the 22nd century, human beings have moved beyond the confines of Earth and have spread out to Mars and Jupiter. Jupiter is "mined" for the natural resources and the laborers work at the space colony called Antilla, which is located on a satellite orbiting of Jupiter. These people living at the "End of the World" are referred to as "Enders." One day, Leo Stenbuck, a young boy with a heart of gold (naturally), is coerced to accompany his friends to the UN Space Force (UNSF) facility to steal from the junkyard, and they get caught. At the same time, the radical military regime on Mars known as Zone of the Enders takes military action on the colony, turning Antilla into a battlefield. The other boys die in front of Leo, who runs off only to wind up inside the very thing the Zone of the Enders were after: the gigantic humanoid weapon "Orbital Frame" called Jehuty. In an effort to return the Frame to its rightful owners and original pilot, Leo battles plenty of other giant robots, protects the innocent and finds time to discuss the ethics of war with ADA, Jehuty's onboard computer.