Yu-Gi-Oh! follows Yugi Mutou, a timid high schooler who is frequently bullied. Yugi loves to play games and, at the beginning of the series, is solving the Millennium Puzzle, an Ancient Egyptian artifact, hoping that it will grant him his wish of making friends. Yugi eventually completes the Puzzle, causing his body to become the host to a mysterious spirit with the personality of a gambler. From that moment onwards, whenever Yugi or any of his friends is threatened, the spirit, briefly possessing Yugi, challenges the antagonist to Shadow Games that reveal that person's true nature, with the loser often being subjected to an adverse Penalty Game. Yugi and his friends gradually learn of the spirit's existence, referring to him as the "other Yugi".