At a construction site, a foreman is pleased that his team are on schedule. Pretty soon these energy discs will start tapping power from the Earth's magnetic field, and they'll have all the heat and electricity they'll need. But as work continues, another group of construction vehicle approach the site.
The foreman yells at them, as he didn't order any more equipment, but then sees that there's nobody driving these vehicles! It's the Constructicons, and the team's leader, Scrapper, says nobody drives them -they drive themselves! The Constructicons steal one of the energy disks. The humans attempt to stop them, but their vehicles are forced to stop by Long Haul's missiles.
Scavenger then takes a power converter, and the Constructicons transform. Scrapper tells the workers that if they interfere with them, they'll be terminated! He then announces that his team will return to their master: Megatron!
The Constructicons return to the Decepticon's temporary base, and Megatron sees they've come back on schedule. He thinks they were worth the time they spent building them in these caverns. He wants a report, and Scrapper says everyone is accounted for...
...Scavenger, Mixmaster, Long Haul, Bonecrusher, Hook, and himself.
As they've got the parts they needed, Megatron tells them to attach them to Scrapper's invention at once. Megatron explains to Starscream that soon, Scrapper's invention will give him the power to defeat the Autobots once and for all. Starscream says to forgive him, but that boast sounds vaguely familiar. Megaton says previous failures were through no fault of his own. But this time things will be different, as this device will allow him to strike through to Optimus Prime's only weakness: his over-developed sense of honor.
At Autobot HQ, Ironhide picks up a signal, and it's clear it's Decepticon activity. But everyone is surprised to see that it's just one Decepticon: Megatron! Cliffjumper immediately tries his glass gas rays...
...but Megatron breaks free from the glass, shattering it. Wheeljack then tries out his new shockblast cannon, but it malfunctions and ends up blowing him up instead.
Wheeljack says that was a shock alright, as Ironhide runs over and starts shooting at Megatron. But Megatron doesn't fight back, and keep avoiding the Autobot's fire. Megatron says he's come to talk, not fight. Optimus Prime tells the Autobots to hold their fire, as Megatron lands. He tells the Autobots he's come about a matter of Cybertron law. Their war has gone on for millions of years, in which opposing leaders, him and Prime, may do battle.
He wants a duel, and the loser must exile himself and his army to deep space for eternity. The winner may stay where he chooses. Does he accept? Cliffjumper doesn't trust him, but Wheeljack says it would end the war. Ironhide tells Prime he could take Megatron, as he's the best. Prime says it is the law of their native planet -so he accepts Megatron's challenge. Megatron tells him he thought he would, as he has such a strong sense of honor. He then leaves...
...and heads straight back to the Decepticon base. Scrapper's invention is ready, and Megatron stands inside it. He tells Scrapper to proceed with the strength transfer, so Scrapper activates his invention and tells the Decepticons that each of them must contribute a power chip rectifier to the exchange furnace. Starscream complains that he needs his power chip rectifier, and reminds Megatron that the Cybertron code of honor requires each warrior to fight as he is. Megatron wouldn't want to cheat, would he? Megatron tells him he will win by any means, and at any cost, even if it means terminating him! Starscream says he was just raising a legal point, and throws in his power chip rectifier. Megatron isn't care about technicalities -only victory interests him!
The other Decepticons drop in their power chip rectifiers, and Scrapper says the critical temperature has been achieved. Megatron says for the strength transfer to begin, and the sequence is started. Megatron surges with energy and demands more, before screaming out. But the strength transfer is a success, and as everything powers down, he tells the Decepticons that he now possesses each of their powers, in addition to his own. Optimus Prime and the Autobots are finished!
Starscream says that if Teletraan I detects Megatron's deception, it'll alert Optimus Prime. Megatron says it won't, and tells Scrapper for him and the other Constructicons to carry out their orders. They head off and start digging their way out. Megatron explains that whilst all the Autobots are watching his fight with Optimus Prime, the Constructicons will tunnel their way beneath the Autobot HQ, then they'll enter the control room and destroy Teletraan I. Megatron clenches his fist and sends energy out, saying that Optimus Prime won't know what hit him!
At the Autobot HQ, Spike isn't crazy about the combat deal. They all know how tricky Megatron can be, they don't call those creeps "Decepticons" for nothing. Prime tells him the code specifies a fair battle, and under those rules, he's confident he can beat Megatron. Besides, if Megatron doesn't abide by the rules, Teletraan I will tell them. The time for the battle approaches, so the Autobots transform and roll out.
They arrive at the battleground and transform. It doesn't take long for the Decepticons to show up, and Megatron welcomes Optimus Prime to defeat. Prime tells him the battle hasn't begun yet. As the Autobots and Decepticons take their places around the arena, Prime tells his opponent to remember the law: this battle is between the two of them only.
The two leaders head down and remind each other of the stakes: whoever loses will be exiled to deep space forever, along with his army. The two shakes hands, but Megatron sends a surge of power through Prime, before effortlessly tossing him back with his one arm!
Prime gets up and says he didn't realize Megatron was that strong. Megatron then uses one of Starscream's powers: a cluster bomb. Prime gets hit and is knocked down.
Megatron keeps firing, but Prime gets back up and manages to fire a blast back. The Autobots and their human friends cheer Prime on, but Megatron then uses Rumble's power, and creates a mini-quake.
Prime almost falls, but manages to hold on and get back up. He picks up a large boulder and throws it at Megatron, but Megatron uses Skywarp's teleport to get out of the way.
He then shoots Prime in the back, knocking him down again. Meanwhile, the Constructicons have made their way to the volcano the Autobot HQ is located in. Scrapper advises caution, as this volcano is active. Scavenger picks up computer signals from above, and realizes that they're directly under Teletraan I.
Back at the battle, Prime refuses to give up and shoots Megatron in the head. He then grabs him and pulls him up into the air, but Megatron says he can't blast what he can't see, and uses Reflector's power to blind Prime and force him to release Megatron.
He then uses Thundercracker's sonic booms to make Prime fall to his knees, before blasting him down again. Megatron tells him he was good, but not good enough to fight him!
Megatron declares it's over, as Optimus Prime has been defeated. Prime is alive but says he underestimated Megatron, he didn't realize he had so many powers. Ironhide wants to fight the Decepticons and rallies the other Autobots, but Prime tells him no -Megatron beat him according to Cybertron law, to violate that law would destroy their honor. They will comply and leave the Earth forever. Ratchet says they'll need Teletraan I to diagnose all of Prime's damage.
Prime is just about able to transform, but Huffer says he'll help and takes Prime's trailer for him. Prime tells the Autobots to roll out -perhaps for the last time. As the Decepticons watch, Megatron tells them they'll follow the Autobots, to make sure noble Optimus Prime keeps his word.
Meanwhile, the Constructicons need a way to get into the Autobot HQ, and Scrapper tells Mixmaster they need acid. Mixmaster uses a blend of chemicals to create a powerful acid laser, which burns a hole at and then through the base. But Teletraan I's alarms are going off, and the Dinobots are alerted that something is wrong. The Constructicons heads into the Autobots HQ...
...and they find Teletraan I. Scrapper tells his team to destroy it, but before they can, Grimlock calls out saying they'll destroy them! The Dinobots open fire, and the Constructicons have no choice but to flee.
They get pushed back outside of the base, as Sludge says he hasn't seen these Decepticons before. Snarl says they won't see them again either, because they'll dino-mite them to pieces! The Dinobots transform, and Sludge stops the ground...
...breaking part of it up, creating a moat of lava. Hook tells Scrapper it's bad news: they've brought out the heavy artillery. Scrapper says it's time they did the same -only heavier. The Constructions transform, combining into one super robot...
...Devastator! Devastator warns the Dinobots to prepare to meet their doom, as nothing can withstand his might! That doesn't stop them from trying, as Grimlock chomps down on one of Devastator's arms. Devastator swats him away, whilst Snarl goes in. He bashes Devastator's leg with his tail, only to get kicked back.
The Autobots arrive back and see the Dinobots, Ironhide says they should help them but Prime refuses, telling him to remember the law. They head inside their HQ, and Wheeljack and Ratchet quickly repair Prime. Wheeljack still can't understand how Megatron got so much strength to beat Prime.
Chip says he does -he just had Teletraan I do an energy scan on Prime's damaged parts, and it displays images of all of the Decepticons. They realize that, somehow, Megatron used the powers of his troops, and cheated to win. Ironhide says that if Megatron cheated, they can ignore the agreement. Prime says that's affirmative, and tells the Autobots the time has come for them to fight back!
Outside, Devastator tells the Dinobots that nothing defeats him -nothing! But then a big, booming voice calls out, questioning if nothing can defeat a little one like him. Devastator and the Decepticons turn around and are shocked to see...
...a giant Autobot has appeared! The Autobot asks what he would say about him, but as this is happening, Prime decides to act before Devastator realizes what is happening. Prime fires one single, powerful shot, that hits Devastator...
...and breaks him back up into the 6 individual Constructicons. The Dinobots go on the offensive, forcing the Constructicons back until they crash into the lava moat. It's revealed that the giant Autobots is nothing more than one of Hound's holograms, which he switches off.
Megatron sees they've been tricked, the giant Autobot was an illusion that wasn't real! Prime says they're real, and he and the Autobots open fire on the Decepticons, making them also all fall into the lava.
Prime personally deals with Megatron, shooting him and forcing him into the lava moat. Prime says that it is ended.
Spike asks if it is really over, have they really seen the end of this war? Prime says who can say -in this vast universe, is anything truly forever? Down in the lava, Megatron reemerges and says they shall rise again!
NOTES
-SCRIPT DIFFERNECES: Click here for details.
-This episode aired late on in 1984, but the Constructicon toys wouldn't be available on shelves until 1985.
-Megatron states that the Constructicons were built on Earth. This will get retconned in season 2... and then the retcon will also get retconned in season 3.
-When the Constructicons are heading towards Teletraan I, at one point Scrapper refers to Scavenger as "Scrounge". This was Scavenger's early name, which was mostly fixed in the revised script, but this one instance slipped through.
-Devastator has two different head designs, both of which are used in this episode (although the second design is only briefly shown):
Personally I prefer the second design more, which is what mainly gets used in future episodes and the movie, although the first design occasionally makes appearances as well.
-When Chip runs the Teletraan I scan, when it shows Rumble (misspelled as "RUNBLE", there is text on the bottom right stating "RED ROBOT":
This proves something many fans wondered was the case: Rumble and Frenzy had their colors switched for the cartoon by mistake. For their toys and comic book appearances, Rumble is red, Frenzy is blue. It was supposed to be this way for the cartoon, but something went wrong and their colors got switched (the Japanese dub did fix this error though and switched the names back). And yeah, cartoon Rumble is purple rather than blue, but shhhhh.
-The reason for the way this episode ends how it does - with the uncertain fate of the Decepticons and the Autobots wondering if the war is over, is probably because it wasn't known at the time if The Transformers would be renewed for a second season. It was, of course, and the second season would start airing in the third quarter of 1985.