Mutou Yuugi and his friends are in their final year of high school and are talking about what they will do in the future. Meanwhile, Kaiba Seto has commissioned an excavation to retrieve the disassembled Millennium Puzzle from the ruins of the Millennium chamber. The item had previously housed the soul of his rival, Atem, whom he hopes to revive in order to settle their score.

The excavation is interrupted by Diva, who faces Kaiba in a game of Duel Monsters and steals two pieces of the puzzle. He keeps one piece to himself and gives the other to his sister, Sera, who passes it on to Mutou Yuugi.

Source: EN Wikipedia