Adam, Man-At-Arms and Orko discover the City of the Ancients, but Skeletor is spying on them via a Robot Bird. Aran and Una appear at Snake Mountain wishing to serve Skeletor, so he sends them to retrieve the Masks of Power. Aran and Una place the masks on their faces transforming them into Deemos and Terella, two powerful magicians from Eternia's past. He-Man battles Aru, the protector of the masks, whilst Deemos and Terella head for Snake Mountain. He-Man, Man-At-Arms and Orko speak to the Sorceress who tells them Deemos and Terella are after the Sword of the Ancients located under Snake Mountain. Deemos and Terella defeat Skeletor easily, He-Man rescues Skeletor, and then a battle takes place under Snake Mountain. The Sword of the Ancients is retrieved by He-Man and joins with his own Sword of Power. With the Sword of the Ancients beyond their reach Deemos and Terella vanish, and Aran and Una return.
Synopsis by Zadoc Angell