When Kaito Kuroba‘s father dies under mysterious circumstances, he finds out his father's secret identity; a famous international criminal known as International Criminal 1412: the Phantom Thief, and that he was murdered by a mysterious organization for refusing to aid them in retrieving the "Pandora Gem" – a jewel that grants immortality. He vows to stop the organization from obtaining the gem, and assumes his father's identity. Kaito researches and steals famous priceless gems with interesting histories from incredibly well-defended areas, but always returns them after the next full moon.