B: The Beginning

On the islands of Cremona, an unscrupulous vigilante known as Killer B is running amok, drawing praise and scorn alike. Armed with his trusty blade and superhuman abilities, Killer B takes matters into his own hands for justice to be served with unrivaled force. Unable to track this outlaw down themselves, Royal Investigation Service employs Keith Flick, an eccentric veteran detective relegated to their Archives Department after suffering personal loss himself; crimes across Cremona quickly escalate from stealthy execution of wrongdoers all the way up until strikes on public figures where multiple individuals may be involved - or more than one person responsible.

With his trusty sidekick Lily Hoshina at his side and unanticipated assistance from Killer B, Keith unravels plots involving secret organizations, domestic terrorism and human experiments. When involvement of RIS goes beyond justice's purview, its involvement calls into question both government corruption as well as trust between close allies.