An ancient box is found and could not be opened even by Goku. They make a wish to open the box and a mysterious person appears saying they should have never done that. The mysterious person Tapion later reveals why he was in the box. To seal up one half of a powerful monster. The other half was gone meaning Tapion's little brother must be dead. Seeing how Trunks thought of him as the brother he never had, Tapion gives Trunks his sword. Goku and everyone does battle with the beast and fail. Goku uses the Dragon Fist technique and kills him. Bulma builds a machine and sends Tapion home.