In order to save his kingdom that has fallen into crime and chaos, the King lowers himself to bargain with a demon to bring about peace once more. To bring about order, the demon curses the King's daughter, Princess Eriza, with an insatiable bloodlust towards criminals. Just when the curse was becoming dangerous for the citizens due to a lack of criminals left for her to execute, the immortal magician Gurem appears… Thus begins the tale of the Sadistic Murder Princess and the Masochistic Immortal Magician.