The “Demon King City,” where humans and demonkind coexist. In this city ruled by seven Demon Kings, one of them has been murdered. Arsarisa, the daughter of a hero who enforces justice under the law, sets out to solve the case and teams up with Keed, a rogue investigator who upholds loyalty over the law itself. In a world swirling with violence and conspiracy, an unconventional investigation led by this mismatched duo begins.