Trouble's Middle Name

The Sunstone, which is held within the Temple of the Sun, is running out of power and must be recharged, in The Ceremony of the Sun, which takes place once a century. The Sunstone's keepers invite He-Man and his companions to the ceremony, but on the way they face trouble from Negator, who wants the Sunstone's power for himself, and even more inconveniently a Trollan called Prankster who is deliberately making a nuisance of himself and will only go home if they can guess his name.