In the year 2025, huge beasts from beyond the galaxy attacked Earth. In the war that followed, humanity fought back with a giant robot named Yukio, piloted by Tetsuo Yabusame, As the massive alien swarm closed in on humanity's homeworld, Tetsuo and the Earth Defense Force deployed for the final battle with the invading horde. They lost... Ten years later, Tetsuo has returned to Earth in an escape pod, but finds the planet totally frozen over! To his horror, he discovers that the alien kaiju are also on Earth. After meeting a hardy band of human survivors, Tetsuo learns that Yukio has survived as well, his consciousness downloaded into the escape pod--which is also a battle robot! But the people Tetsuo has found are not the only survivors, and a mysterious humanoid kaiju also lurks among the ruins...