The Dreamstone (1990)

Urpgor's niece, Urpip has arrived, and is immediatly used by her uncle in a devious scheme to enter the Land of Dreams using a new Noop suit he has designed. But Urpip wants to take the Dreamstone for herself and flees using one of Urpgor's submarines, disguised as a Noop, she begins causing trouble that even the real Noops find diffucult to deal with.