After The Biggest, Most Awful, Most Tragic Event in Human History, an organization known as Future Foundation was created in order to save the world. In addition, the Special Crime Investigations division was formed with the sole purpose of investigating bizarre and grotesque murders. Their newest recruit, Misaki Asano, is bright, cheerful, and despises gore—yet that does not stop her from striving to bring light in a world ridden with despair.

Partnered with the eccentric slob Takumi Hijirihara, Misaki's first job is to investigate the discovery of several corpses at an idol's concert. Although Hijirihara has solved the case swiftly, the culprit is soon discovered cleanly dismembered by a mysterious murderer of murderers known as "Killer Killer." Only leaving behind a cute note at the scene of the crime, Killer Killer has been eluding the Foundation for a long time, but the mastermind behind these slaughters may be closer than they realize.