Dexter must save Japan from being destroyed by a monster, but his robot must be controlled by four people to function correctly, so Dexter must tell Dee Dee... and his parents.
Mandark doesn't know that his pet duck is really Quackor the Fowl, Monkey's rival. Quackor overhears Mandark talking in his sleep about destroying Dexter's lab and tries to do it, unaware that Monkey is Dexter's pet.