Young Shinoha Tanaka, who has lost the ability to laugh, meets Kiwami Kimura, an office worker who shares his love of anime. The two hit it off, but it turns out they are actually members of rival forces that have been killing each other since the Edo period - ninja and gokudo! "If you misbehave in the underworld, the ninja come a-calling." Ninja and gokudo - who will survive and who will perish?