After many years of peace on the planet Eternia, the Mystic Wall that has held evil back for so long begins to weaken. As the Royal Palace celebrates the sixteenth birthday of Prince Adam, Skeletor and his Evil Warriors finally succeed in destroying the Mystic Wall. Adam's mentor Man-At-Arms takes the teenager to the mysterious Castle Grayskull where a being known only as the Sorceress explains the history of evil on Eternia, and the very special destiny that awaits Adam...

Prince Adam arrives on the battlefield in the Evergreen Forest to witness the heroes of Eternia facing defeat at the hands of Skeletor's Evil Warriors. Skeletor and Beast Man take to the skies on their Griffins with King Randor as their captive. After witnessing all of this, Adam hurries back to Castle Grayskull where he seeks out the Sorceress and openly accepts his destiny as He-Man...

With the arrival of He-Man the tide of battle turns in favor of the heroes. With the Evil Warriors  at bay, the most powerful man in the universe approaches the heroes dubbing them the "Masters of the Universe". Leaving the Masters of the Universe to once again battle the Evil Warriors, He-Man and Battle Cat race across Eternia in an effort to save King Randor from Skeletor...

Wanting to prove himself, Prince Adam believes He-Man may not be needed if he steps up in battle. Meanwhile at Snake Mountain Skeletor tells his Evil Warriors that He-Man's sentimentality is his weakness and orders the capture of Adam in order to lure He-Man into a trap. When Adam is captured by the Evil Warriors he is separated from the Sword of Power, which is sent back to the Royal Palace. Realizing the true urgency of the situation Orko and Cringer journey to Snake Mountain in order to save Adam...

Preying on the fragile truce between the Andreenids and the Avionians, Skeletor starts a war that threatens to tear the Mystic Mountains apart. As both tribes wage war in the skies of Eternia, Skeletor successfully obtains Ambrosia, a miracle Andreenid food that gives power to the individual who digests it. He-Man and Teela arrive to stop both the war and Skeletor...

An unexpected power surge across Eternia prompts the heroes and the villains to search the Sea of Rakash for answers. It becomes apparent that the Coridite  crystal, long thought destroyed, still exists in the possession of Mer-Man. Man-At-Arms manages to grab the Coridite but Mer-Man prevents the hero from escaping. Just as Mer-Man is about to retrieve the crystal, his large fish ally swallows Man-At-Arms and the Coridite crystal! Unexpectedly, the Coridite causes a mutaion inside the giant fish, making the creature extremely powerful and dangerous...