Early 21st Century Earth. A pretty normal Earth, by all accounts. Nothing out of the ordinary, with politics and video games and television. At least, mostly. The moon is missing a good chunk of its mass, and the various governments are close-mouthed about how, but everything seems to have calmed down since that incident less than a year ago. Hasn't it?
But underneath it all is a world of intrigue and danger. Political maneuvering that brings about dangers to all, bioengineered superweapons, and fantastically skilled assassins all attempting to kill a single powerful being, a being so strong it threatens to destroy the world. A being that has a bounty of over 10 billion Yen upon his head, for any who can kill him.
Currently, he's a teacher of Class 3-E at Kunugigaoka Junior High School, and the middle school students there are the best chance humanity has to defeat this monster.