Yu-Gi-Oh! stars Yugi Mutou, a shy boy who loves games and is often bullied. After solving an ancient artifact known as the Millennium Puzzle, his body becomes the host of a mysterious spirit known as Dark Yugi, who has the personality of a gambler. When Yugi or his friends are threatened by those with darkness in their hearts, Dark Yugi reveals himself and challenges them to a "Shadow Game" (闇のゲーム, Yami no Gēmu; "Dark Games") that reveals the true nature of someone's heart, with their losers being subjected to a dark punishment called a "Penalty Game". Throughout the series, Yugi and his friends Katsuya Jonouchi, Anzu Mazaki, Hiroto Honda, and later Ryo Bakura learn that this other Yugi is the spirit of a nameless pharaoh from Ancient Egypt times who has lost his memories. As they attempt to help the Pharaoh regain his memories, they are put to the test, wagering their lives facing off against others who wield the mysterious Millennium Items and the dark power of the Shadow Games.
