After being suddenly transported to another world, Subaru Natsuki and his new female partner are brutally murdered. However, Subaru awakens to a familiar scene, meeting the same girl again. The day begins to mysteriously repeat itself.

When a kingdom is taken over by tyrants, the deposed princess begins a quest to find a disbanded group of evil knights to help take back her realm.

Genius investigator Keith Flick rejoins the royal police force just as serial killer "B" emerges. Mysterious youth Koku may be an ally, or a target.