Having at last achieved his Perfect Form, the evil Cell's powers have soared to terrible new heights, overshadowing even the greatest of the Z-Fighters. Eager to demonstrate these newfound abilities and prove superiority, Cell proposes a tournament.
In the future, human civilization has been destroyed. Paradox travels back in time to prevent the destruction of his timeline from occurring by eliminating the source of that destruction: Duel Monsters and its creator, Maximillion Pegasus.
Ten year old Haré enjoys a peaceful life until his mother adopts an orphan girl named Guu. Guu turns poor Haré's life inside out when she reveals that she's actually a mind-reading, magic-using monster with a taste for driving Haré insane!