He-Man and the Masters of the Universe

Zodac comes to Grayskull and tells The Sorceress that Eternia is in great danger as Skeletor is searching for the Starseed, the single most powerful object in the universe- a small chunk of cosmic matter left over from the big bang, which can turn its holder's thoughts into reality. The Sorceress summons He-Man, and together with Battle Cat and Orko, he sets off on a race to reach the Starseed before Skeletor does. But given that the Starseed is able to give anyone all the power that they want, is even He-Man strong enough to resist being corrupted by its power?

Skeletor tricks He-Man into thinking he has accidentally killed a man and, consumed by guilt, He-Man transforms back to Adam and drops his sword down the abyss of Grayskull, deciding he is no longer worthy of Grayskull's powers. Skeletor then opens a portal to the goblin world, enabling General Tataran's army to enter Eternia, with possibly enough power and strength to conquer the planet. Can Eternia survive without its greatest hero... and will Adam realize he has been tricked before it is too late?