Heavy Metal War

Out in the middle of nowhere a team of builders are busy making a power station and putting in a device which can draw in magnetic energy which will generate electricity. As the device is put into place a rumble is heard some distance away and the humans turn to see several green construction vehicles heading straight towards them, despite that no more equipment is needed.
 

After seeing that nobody is driving these machines, one of the vehicles says that they are the Constructicons and the group start to steal various things from the building site, including the energy device. Despite the human's best attempts to stop the theft the Constructicons get what they came for and then transform and fly off back to their leader Megatron.


Returning to a hidden Decepticon base in a mountain, Megatron welcomes back the Constructicons who introduce themselves...


Scavenger, Mixmaster, Longhaul, Bonecrusher, Hook and Scrapper.
 

With the stolen goods they have, Megatron orders his new troops to start using them on their invention. Megatron has devised a plan which involves using Optimus Prime's over-developed sense of honour to his advantage. Later on Megatron heads over to the Autobot base and tells them that he wants to talk, not to fight.
 

Optimus stops the Autobots from firing on Megatron, and he heads down to talk to Prime about a matter of Cybertron law - Megatron says that he and Prime will fight each other and whoever wins gets to stay on Earth whilst the loser most exile themselves into space. And because Prime loves his Cybertron laws so much, he agrees much to the delight of Megatron. The Decepticon leader then heads back and goes inside the completed machine the Constructicons were working on.
 

The plan is simple enough: Megatron won't fight fairly and instead will increase his power significantly by using the power chip rectifiers of every Decepticon to gain new powers he can use in the fight. The Decepticons all place their chips inside part of the machine and then watch as the transfer is completed and Megatron is made more powerful than ever.
 

Starscream then raises a fair enough point -Teletraan-1 will no doubt scan Megatron as he and Prime fight and when it does, it will find out about Megatron's cheating tactics. But Megatron's got another plan and has a mission for the Constructicons - he sends them on a drilling mission to get underneath the Autobot base and then destroy Teletraan-1.
 

At the Autobot base Spike expresses his concern over the coming battle and hints to how the Decepticons don't fight fairly, but Optimus Prime believes that Megatron will fight fair as it's a matter of Cybertron law. And with that, Optimus and the other Autobots roll out and take Spike, Sparkplug and Chip with them to the place of battle.
 

With both sides taking their seats the leaders head towards the middle of the arena and remind each other of the rules: whoever loses this fight must take himself and his army to deep space forever.
 

Megatron starts the fight by throwing Optimus and then starts to do things which surprise Optimus, such as creating an earthquake and shooting a cluster bomb. Optimus tries to fight back and picks up a large boulder and hurls it at his foe...
 

...who seems to just let it pass right through him. It seems he can teleport now too and reappears behind Optimus and blasts him with a shot from his fusion cannon. Optimus falls down but he isn't defeated yet.
 

Megatron continues to use powers that Optimus never knew he had, including shooting soundwaves out of his hands. Eventually Optimus gets shot again and finally falls down for good, defeated. Megatron tells Prime that he was good but not good enough to take him on and then tells the Autobots that they must now exile themselves into deep space.
 

Optimus is still alive and the Autobots surround him as he gets back up again. Ironhide wants to go take on the Decepticons right now but Optimus tells them to do nothing of the kind as they must now gather up the Dinobots and then will have to head off into space and exile themselves forever. Not arguing with their leader, the Autobots transform and roll out for what Prime fears is the last time.
 

Meanwhile at the Autobot base, Teletraan-1's alarm systems go off as it finds out that several vehicles are underneath it. The Constructicons have completed their mission and they blast a hold through the floor to get inside. They find the computer and are about to destroy it when the Dinobots arrive after coming to find out what all the noise is, and they open fire on the new enemies.
 

The Constructicons are forced to retreat and end up back outside the Autobot base. Overpowered by the Dinobots, Scrapper decides that it's time to show them what they can do and all six of the Constructicons transform into a giant robot who calls himself Devastator. Devastator starts to beat up the Dinobots as the other Autobots arrive back but don't bother to help -Prime won't let them.
 

Inside Ratchet and Wheeljack quickly fix up Optimus Prime and Chip points out what Teletraan-1 is displaying - Megatron somehow used the powers of all the other Decepticons! Because Megatron cheated, the law is void and they won't be going anywhere, and instead head out to go fight the Decepticons.
 

Back outside Devastator tells the Dinobots that nothing can defeat him, but then a voice cries out and all the Decepticons turn and look in horror at a giant Autobot who laughs at them and laughs at Devastator for being so tiny compared to him.
 

Optimus and the other Autobots are watching as the Decepticons don't have a clue on what they are doing. Optimus then shoots Devastator who breaks down back into the six Constructicons and all of them drive into a lava pool thanks to Dinobot fire.
 

The giant Autobot was nothing more than one of Hound's holograms, but the other Autobots are real and start firing on the Decepticons, who back off but all of them but Megatron end up falling into the lava.
 

Optimus tells Megatron that he won't have to face every Autobot at once, he'll just have to face him. Megatron attempts to shoot Optimus but is too slow and Optimus blasts Megatron off the side of the ledge and into the lava. The Autobots look over but there are no signs of the Decepticons.
 

As the Autobots ponder over what will happen now, Megatron surfaces out of the lava and says that they will rise again. And that wraps up the first season of Transformers.

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 yet if Transformers would be renewed for a second season. It was, of course.

Megatron says that the Constructicons were actually built on Earth. This gets retconned in the second season episodes "The Secret of Omega Supreme".

This episode has remastered horribly and this video reveals everything:

As you can see, the new version looks like shit and is the poorest remaster done out of all the Transformers episodes. Sadly most DVD versions of the episode use this version.