When high school student Yuugi Mutou solves the mysterious Millennium Puzzle, he unleashes another Yuugi, a special presence within. Now every time he is faced with a dilemma, this mysterious alter-ego makes an appearance and helps him with his problems. Yuugi and his companions face several opponents in 'Duel Monsters', a challenging card game used by humans to steal the Millennium Puzzle and harness the great power it contains. The questions pile up and it isn't long before they discover that there is more than pride at stake in these duels.