In this adventure, Prince Planet must break his word to Diana after promising her that he would not use the force of the pendant again, because the use of force is evil. He does use it after all, because, faced with the terrible Devil Fish one one side, and the Iron Shark on the other, he has no choice! And even with the help of the fantastic pendant, can Prince Planet win out against evil men and undersea monsters? Can he escape from the terrible curse of the Sword of Zangar?
—MGM