Despite her ordinary appearance, Kusakabe Maron is not your typical high school girl - she is the embodiment of Jeanne d'Arc. Guided by the angelic Fin Fish, Maron spends her nights as the notorious thief Jeanne, sealing malevolent entities hidden within valuable artwork by preying on their owners' vulnerabilities. Unfortunately, her successful missions lead to accusations of theft, as the artwork vanishes along with the demons. Complicating matters further, a new neighbor and rival thief named Sinbad emerge, and Maron's closest friend is the daughter of a vigilant detective determined to capture her. With these obstacles, Maron's crusade as Jeanne becomes all the more challenging.