He-Man, legendary defender of the planet Eternia, has been summoned to the futuristic planet of Primus to defend the planet from the evil Mutants of the neighboring planet of Denebria. But his old adversary Skeletor has followed him and allied himself with the Mutants in his fight to conquer the whole universe. Together with a team of Galactic Guardians, He-Man fights to defend Primus and all its power resources from the continuous attacks by Skeletor and the Mutants.