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?

He-Man's sword is taken by a peaceful race of Rock People who believe the sword gives them power. Fearing that himself and Battle Cat may never be able to become Adam and Cringer again, He-Man must journey to the underground world of the Rock People to recover the sword.

Prince Adam, Man-At-Arms and Orko are searching the Vine Jungle for the legendary Stone City- but unbeknownst to them, they are being followed by Evil-Lyn, Webstor and Kobra Khan, who are after the city's treasures. By stealing a map, the villains beat the heroes to Stone City, which is filled with realistic-looking statues. When teleporting a life-bringer machine to Snake Mountain, Evil-Lyn accidentally revives the city's warrior king, Vokan! Vokan reveals that his people have been sleeping in stone for thousands of years, to be awakened when Eternia next needs their help. When he notices the life bringer is missing, Evil-Lyn tells him that it is located in Castle Grayskull. Before long, Vokan himself is attacking Grayskull, unwittingly being used by Evil-Lyn, who wants to gain the castle's powers!

The Sorceress sends He-Man, Man-At-Arms, Orko and Battle Cat back in time after Skeletor, who, with Tri-Klops and Fang Man, has gone back into Eternia's past to plant an effective time bomb on the spot where Castle Grayskull now stands, that will destroy it in the present unless He-Man manages to stop it "in time"...

As Prince Adam and Teela attempt to fix a broken-down Attak Trak in the desert, Orko stumbles upon the wizard Kothos, who was transformed into a sand slug by Evil-Lyn in the earlier episode "The Witch and the Warrior". He turns him back to his true form, but has made a mistake as Kothos captures the heroes and offers them to Skeletor in return for his second-in-command, Evil-Lyn, upon whom Kothos is determined to enact revenge.

Teela and Orko are returning from admiring one of the Eternian farmer's bumper crops, when strong tremors suddenly shake the ground and whole crops disappear. Teela is sucked underground with one of the tremors, where she finds herself in the tunnels of an underground community called the Belats. While Orko raises the alarm, the Belat's King, Subternias, who is determined to feed his people no matter what, holds Teela prisoner, and she finds that the Belats are not evil, but are very mistrusting, after being tricked by Skeletor years before...

When Beast Man crashlands by Palace Eternia in one of Skeletor's shuttles, Adam, Teela, Man-At-Arms, Man-E-Faces and Ram Man discover that he was being sent to the Dark Moon of Eternia. Curious as to why Skeletor wanted to send him there, they imprison Beast Man in jail and take the ship up there themselves. Reaching Eternia's Bright Moon, they discover that Eternia's two moons are at war with one another after a resident of the Dark Moon reported seeing the people of the Bright Moon causing severe destruction on the Dark Moon. Knowing that the residents of the Bright Moon are innocent, the heroic warriors realise that Skeletor must be the real cause of the destruction, and so Man-E-Faces disguises himself with a Beast Man costume, and goes to the Dark Moon to spy on Skeletor and his warriors and foil their scheme.

Man-At-Arms almost kills the King and Queen when a device accidentally malfunctions, and fearing his skills are weakening with age, considers resigning from his position. Skeletor takes advantage of the situation by installing an energy bug called Byte into the Royal computers to make all the machinery malfunction. Can He-Man find the cause of the problem before it is too late?

Dree Elle comes to Eternia to enlist Orko's help, explaining that an ambitious Trollan wizard called Snoob has defeated Uncle Montork and taken his position as head of the Academy of Magic. Since Montork claims to have felt inexplicably weak when fighting Snoob, they suspect unfair play was used. Orko and Dree Elle go to Trolla, followed by He-Man and Battle Cat, and it soon transpires that Snoob is being controlled by Whiplash, who is trying to learn magic in order to impress Skeletor. It is up to He-Man to stop his scheme, with the help of his Trollan friends!

Skeletor uses a teleportation device to teleport The Sorceress, in the form of Zoar, to another planet. As He-Man and Battle Cat go to this planet to rescue The Sorceress, Teela is given the task of guarding Grayskull in The Sorceress' place. Unaware that someday she will inherit the position of Sorceress for good, will she be able to live up to her destiny?

When exploring an ancient temple, Prince Adam and He-Man come across the Masks of Power, which conceal the spirits of an ancient evil race. Two power-hungry travellers steal the masks, and their bodies are possessed by the spirits within them. Together they go to Snake Mountain, where they offer Skeletor their services- but Skeletor will only recruit them after they have passed a series of tests, one of which involves recovering the Sword of the Ancients from deep within Snake Mountain.

Once again, Granamyr asks for He-Man's help. The dragons of Eternia are mysteriously disappearing and Webstor and Kobra Khan seem to be behind it.

An inventor called Zicran visits the Royal Palace to deliver a Transmutator machine to Man-At-Arms, accompanied by his daughter Ileena, a friend of Teela's. Ileena is vulnerable and lacking in self-confidence, feeling inferior compared to Teela's agility. Meanwhile, an evil sorcerer called Jarvan, who was previously defeated by He-Man and Man-At-Arms, has escaped from the prison mines and has set his sights on the Transmutator. Preying on Ileena's depression, he disguises himself as a kindly old woman and gives Ileena a 'magic potion' that will boost her confidence and strength. But the potion contains a dangerous drug, and Ileena soon finds herself addicted to the drug, and almost causes several serious accidents while under its effects. She also finds herself unwittingly obeying Jarvan's commands, and helps him to obtain the Transmutator! Can the heroic warriors cure Ileena's addiction before she causes more damage to herself and the people around her?

While entertaining the Royal Family with his magic, Orko finds his act interrupted by a strange sorceress called Majestra. Majestra performs a trick in which she appears to make the King vanish then reappear- but in fact, Majestra is really Evil-Lyn in disguise, and has teleported the King to the dungeon and replaced him with a disguised Beast Man! Evil-Lyn has found a magical Shaping Staff which can transform anything into whatever the holder wishes- and under their disguises, Evil-Lyn and Beast Man set about causing havoc around the palace, turning each member of the Royal Family into helpless animals, while Skeletor awaits them at Grayskull with his latest creation- an evil version of He-Man, called Faker!

Negator, an evil character with a love of computers and electronics, sees Man-At-Arms testing out his latest invention, the Beam Ray, in the desert. Impressed, Negator wants the scientist to come and work for him, so that he can use his creations for his own evil purposes. When Man-At-Arms refuses, Negator captures Teela to force him to come to him. As He-Man, Ram Man and Battle Cat search for their missing friends, they are sucked into Negator's underground electronic domain, and Negator sends He-Man and Ram Man into his living electronic "game"...

Adam and Teela visit an ancient castle where an evil Lord and Lady once lived, practising black magic by absorbing energy from the trees, until the trees died and they began a centuries-long sleep in their coffins. As Adam and Teela ride some winged horses, Lady Valtera and Lord Tyran awake from their coffins. Lord Tyran's appearance has been greatly disfigured by his evil ways- so severely that Valtera does not recognise him. When Valtera comes across Adam and captures him to be her slave, Tyran thinks she is more interested in Adam than him and wreaks havoc attempting to gain all the power he can, and capturing Teela along the way.

A spacefaring gladiator called the Game Master lands on Eternia, intending to capture He-Man to make him fight for his amusement. But when he sends his minions out to find He-Man, he is in the form of Adam and so He-Man is nowhere to be found. So instead they capture Teela- but they also take Adam's Power Sword, meaning he is faced with the task of rescuing Teela as Adam!

Malik, the Wizard of Stone Mountain, calls He-Man and Teela to his aid when the Fountain of Life of Aridan is stolen by the evil wizard Kothos. But just as the heroes confront Kothos in his floating palace, Skeletor sends Evil-Lyn and Clawful after the fountain- and Evil-Lyn ends up stranded in the desert with Teela, her magic wiped away. In spite of their rivalry, Evil-Lyn and Teela have no choice but to work together and form an alliance to get themselves back to safety. As they put aside their differences, they form a surprisingly effective duo- and both learn a thing or two about the other in the process.....

Strange living plants are gradually taking over Eternia. He-Man accuses Skeletor, and Skeletor accuses He-Man, but the real culprit is a curious plant-man called Evilseed, who intends to take over the whole planet with his plants. He-Man and Skeletor must reluctantly combine their powers in order to wither Evilseed's plot...

Orko runs away, thinking his friends don't really like him. The Sorceress solves his problem, but on his way back to the palace he is captured by Skeletor, who puts him under a spell to reveal the riddle of the jaw bridge. Skeletor uses this riddle to break into Grayskull, and The Sorceress must defend the castle while He-Man tries to free Orko.

Man-At-Arms is testing out a new duplicating machine, which can make a replica of any solid object. However, the machine is not yet perfect and so its replicas come out being half the size of the original objects. But Skeletor steals the machine, and he uses it to create a whole army of miniature Skeletors to do his bidding... and before long, the palace is overrun with Skeletors!

Skeletor captures Teela and Orko, and sends them to be imprisoned in the dark, dismal kingdom of Morragor, ruled over by an enslaved monster in thrall to Skeletor. But the monster, despite his gruesome appearance, comes across as noble and friendly, and treats his captives with utmost dignity. As He-Man journeys to rescue his friends, Teela, seeing the monster's true personality beneath the surface, encourages him to break himself free from his unwilling devotion to Skeletor.

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?

An alien race called the Vendari, which knows no evil, visits Eternia, wishing to see the difference between good and evil for themselves, and which side is stronger. They select Fisto from the side of good and Spikor from the side of evil, to compete against one another in a series of games. However, Fisto's chances of victory are threatened by Skeletor and his crew, who refuse to play fair and do all they can to ensure Spikor emerges victorious.

Kobra Khan visits the heroic warriors, offering a truce in exchange for their help. He tells them that his people, the Reptons (a snake clan to whom he belonged before he joined Skeletor's forces) are in need of help- someone has extinguished the furnace which heats their underground kingdom, plunging the whole kingdom into severe coldness. Khan wants them to find the culprit and re-heat the furnace. He-Man, Man-At-Arms, Battle Cat and Orko go to the Reptons kingdom with Khan, but it soon transpires that Khan is not to be trusted... for it was he who extinguished the furnace himself, and he intends to frame He-Man for the crime and expose them, in the hope of gaining the Repton King's crown in return!