Two Earth astronauts, Mark Blaze and Andrea Steele, are on a mission to save Earth from a meteor that is about to collide with the planet. but on their mission, they are sucked through the same portal which brought Marlena to Eternia, and they find themselves on Eternia, now ruled by the missing astronaut Marlena Glenn. And things turn drastic when Skeletor captures Blaze, and steals the ship's missile, intending to use it to blow up Grayskull! Can He-Man stop Skeletor's scheme... and can he help Blaze and Steele to save Earth before it is too late?