In 2041 AD, a new enemy called Zeravire appears in the solar system, annihilating every military installation it encounters. Wealthy industrialist Klein Sandman, who had already anticipated the invasion, has been quietly preparing his forces. His key asset is the Gravion, a giant robot that draws power from gravity. At the same time, young Eiji sneaks into Sandman’s base in search of his missing sister. There he meets another young man named Toga. Together, along with four other pilots aboard the Gravion, they must team up to fend off the Zeravire threat.