Kaito Kuroba, a little naughty but otherwise typical youngster, finds a stunning fact eight years after his father's tragic death: the Phantom Thief Kaito Kid—also known as "The Magician Under the Moonlight"—was none other than his own father. The former thief was assassinated by a criminal group looking for a mythological stone known as the Pandora Gem, which is claimed to shed a tear with the passing of the Valley Comet every ten thousand years. The diamond is said to bring immortality when the tear is devoured. Kaito dons the Phantom Thief's disguise, vowing to put those responsible for his father's death to justice, stealing costly jewels night after night in order to uncover the Pandora Gem before his adversaries can utilize the power for themselves.