In the kingdom of Forland - the stronghold of an ancient and powerful magic - a bloody coup led by the former court scientist Professor Akamashi and his killer henchmen drives the royal family to the brink of extinction. Only the young princess Arita manages to escape. There she collides with the notorious bounty hunter Falis, where the souls of the two disparate girls swap bodies. Arita, who is now in the body of the brutal fighter, makes her an offer: Falis, who has murderous powers, is to recapture Arita's kingdom; in return, Falis is allowed to live the life of a real princess in her new form - this heralds the birth of the "Murder Princess"...