The game takes place in a fictional, future version of Tokyo that has been left in ruins due to the invasion of space aliens called "Gigants". While the entire Earth has been largely laid to waste, before complete destruction, the game's primary character, Ichiya Amakaze, is finally able to defeat a Gigant with a mysterious power called "Yorigami". Source: Wikipedia, "[en.wikipedia.org/wiki/Ray_Gigant Ray Gigant]", available under the CC-BY-SA License.