On Daisuke Niwa's fourteenth birthday, Risa Harada, the girl he tried to give a love letter to, told him, "You're a good friend". That day, when the heartbroken Daisuke thinks of Risa, he suddenly transforms into the legendary great phantom thief, Dark. And he has to go, according to the note his mother left, to steal the Sacred Maiden.!? It's Daisuke and company's adventures on streets that resemble Europe! Later Daisuke and Risa's older sister Riku fell in love with each other.