On his fourteenth birthday, Daisuke Niwa is rejected by his crush, and then finds his body transformed into the legendary thief called Dark Mousy because of the DNA he has inherited from his mother's family. The only way for Daisuke to control his transformation is if the person he loves, loves him back. Now whenever Daisuke is around someone he has a romantic interest in, he transforms into Dark. Daisuke's troubles continue since he has to perform nightly art museum robberies as Dark while unwitting the mysterious boy genius and commander of the operation to capture Dark, Satoshi Hiwatari.
(From Animes News Network)