Daisuke Niwa was just your average middle schooler pining away after his unrequited love. Well, average except for the odd training his mother put him through, planting traps for him when he returned from school to test his agility and problem solving. But that all changed on his 14th birthday, when, after being rejected by his crush Risa, he suddenly transformed -- appearing much older, and his hair color changing to purple. His mother happily informs him that this is normal -- for hundreds of years, every generation of males in his family undergoes a transformation into the "legendary phantom thief, Dark" when they experience the feeling of love, thanks to a unique "genetic condition". Until the girl he loves returns his feelings wholeheartedly, Daisuke must transform into Dark and steal