Followed a blond warrior named Prince Adam who, when uttering the magic words, "By the power of Grayskull - I have the power," turned into the heroic He-Man. He and his allies - Battle Cat, Man-at-Arms and Orko - defended their planet Eternia from the evil forces of Skeletor, who tried week after week to conquer the fortress Castle Grayskull, which imbued He-Man with his powers.