On Cybertron, Springer moves a new power core into place. Perceptor says it's completed at last -this new power core will triple Cybertron's energy reserves. Ultra Magnus tells him that it's a great achievement, but asks if he's sure the city can safely handle the excess power. Perceptor says they've taken every precaution, but just in case there should be a power overload, activating this lever will jettison the power core into space, before an explosion can occur.

The power core is inserted successfully, and is activated. The Autobots celebrate, as Springer says the power core will keep Cybertron lit for centuries. Elsewhere, the Quintessons are watching from a ship. The Quintesson leader says it's remarkable accomplishment, but it makes him hate their rebellious constructs more than ever. They were once the masters of Cybertron, until the Autobot's ancestors forced them into exile. Through the ages, many groups of Quintessons have tried to retake Cybertron, but none have succeeded.

A Quintesson scientist says that's until now. He says that to secure Cybertron for the future, they can draw on help from their distant past. He reminds them of their first experiments in cybernetic construction: the Trans-Organics. Another Quintesson says the Trans-Organics were only a legend, but the scientist says they're not to the one who built them. He explains that they were the first attempts at creating a race of subservient cybernetic warriors, which were half beast, half machine.

But the process was too unstable, and the Trans-Organics were judged to be unfit for even simpe tasks. One of the Trans-Organics, who had originally been designed to be a living energy siphon, turned on them.

It was during the fight that the scientist lost one of his own faces to the beast. The Trans-Organics that they couldn't destroy were locked away in a hibernation chamber, located deep within Cybertron. The Quintesson leader says the rumors they've heard about a massive creature that dwells beneath Cybertron are true. The scientist says that if the Dweller could be released again, he predicts it would destroy every robot on Cybertron. The leader is interested as it means they could then claim Cybertron, but wonders how they could release the Dweller without being destroyed themselves. The scientist says they'll leave that to the Decepticons.

On Chaar, Galvatron is yelling at the Sweeps, asking why he's still stuck on the cosmic trash bin, why hasn't he re-taken Cybertron, and most importantly, why has be been saddled with such a useless pile of rusting junk for followers? Scourge tries to explain that he and and the Sweeps need energy.

Galvatron punches him into the Sweeps and tells him if he wants power, he'll give it to him. Before he can fire, a bright beam of energy hits the ground before him.

The Quintesson leader and scientist appear through the beam, offering the Decepticons greetings and an offer. Galvatron says they betrayed them to the Autobots, so why should they listen to them? The leader says he can't lay one bad experience on the doorstep of the whole Quintesson race. Besides, how can he be so certain they were the ones that betrayed him? Galvatron says they do all look alike, but then tells them to state their offer. They show a hologram of the Autobot's new power core, and the leader tells Galvatron to think about it -enough raw power to make the Decepticons the ultimate force in the galaxy. Galvatron asks what's in it for them, but the scientist says to think of it as a peace offering to strengthen the alliance between Decepticons and Quintessons.

The Decepticon quickly head to Cybertron, and kick down a door. Scourge wonders if this abandoned shaft could really be the entrance to the power core, and Galvatron says it had better be, for the Quintesson's sake. As they head in, Ultra Magnus yells out, telling them to stop where they are. Galvatron spins around and fires a few times...

...burying the Autobots under some rubble. Scourge says that won't hold them for long, but Galvatron says once they reach the power core, they'll have enough power to stop an army of Autobots. Out in space, the Quintessons are monitoring the Decepticons from their ship.

The scientist says everything is going as precisely as calculated. Soon, the unwitting Decepticons will unleash the Dweller, and all the Transformers will be doomed. They decide to witness their victory first hand, and head to Cybertron. Back on Cybertron, the Autobots free themselves from the rubble, and take a look at the shaft entrance. Arcee wonders why the Decepticons picked this particular shaft, as it has been closed for ages, and leads absolutely nowhere.

The Decepticons reach the lowest level of Cybertron, but Galvatron is annoyed to see there's no sign of the power core. Scourge and a Sweep punch down a door, and see another behind it.

Galvatron says that's it, and blasts it down. They run into a chamber, which has a machine in it, but no power core.

Galvatron says the Quintessons will pay for this, and blasts the machine in frustration. In doing so, it causes the pods it is holding to break away from the machine, which open up. The Decepticons start to leave when Scourge is suddenly grabbed...

by the monstrous Trans-Organics! The Trans-Organics have all been released, and stare at the Decepticons.

Scourge begs for help, and one of the Trans-Organics smacks him in the face. Galvatron says to destroy them, and a battle begins.

As Galvatron takes on several of the Trans-Organics by himself, he says there are too many of them.

The Autobots are on the trail of the Decepticons, and Kup says he didn't know the old tunnels went down this far. Springer says from the looks of things, nobody has been down here in centuries. They then hear the Decepticons screaming nearby, and rush in to find them fighting the Trans-Organics. Some of the Trans-Organics then turn their attention towards the Autobots, but Wreck-Gar destroys one of them.

Galvatron blows a hole through a wall and tells the Decepticons to follow him, as the Autobots can serve as a sacrifice to the Trans-Organics. They enter another room and try to find another exit, but Cyclonus says there is something in this chamber.

The something is the Dweller, which reveals itself by grabbing a Sweep and draining him of all his energy. The Sweep turns gray, as Galvatron orders the Decepticons to kill the Dweller.

The Dweller fires a net out of its mouth, which captures another Sweep, and then also drains him of his energy. The Dweller then stores the two drained Sweeps inside its own body.

Galvatron says they stand a better chance against the others, and head back to the previous room. The Dweller follows them and attacks Ultra Magnus, but Wreck-Gar saves him by cutting the Dweller's net with his axe. But then he gets caught in another of the Dweller's nets.

The Decepticons attempts to flee, but the Dweller grabs and drains Scourge before he can escape. The Dweller then takes on the remaining Trans-Organics, which it does by grabbing them, and then draining them...

...which results in their organic matter vanishing, only leaving behind a pile of parts. Springer thinks there is still a chance to save Wreck-Gar, and evades the Dweller's attacks enough to be able to get on top of him. He manages to pull Wreck-Gar out.

But when he lands, Wreck-Gar's eyes glow red and he tells Springer to feed him. He starts to drain Springer, but then the Dweller grabs him and completely drains him of his energy. As Wreck-Gar starts to try to drain the Dweller itself, the Autobots see that their friends have been turned into some sort of energy vampires. Magnus says if they can lure it out of this chamber, they'll have more room to fight. Arcee gets cornered by the Dweller.

Kup tells her to come this way, but then the Decepticons attack them from behind. Kup and Magnus get knocked down, and the entrance to the chamber is sealed by the rubble.

The Dweller then captures Arcee in a net, but she transforms and tries to pull away. The energy vampires go after her, but Kup recovers and knocks them down. He then breaks the Dweller's net.

But then the vampires catch up with him and turn him into a vampire. Magnus stops Arcee from going after them as he tells her there is nothing they can do for them now, but maybe Perceptor will know a way to cure them. He blasts apart the rubble...

...and the two of them head back towards the surface, with the Dweller and vampires in pursuit. Meanwhile, the Quintessons discuss how Cybertron will be theirs again soon. The scientist calculates that they've already unleashed the Dweller, which even now should be destroying Autobots and Decepticons alike. The Quintesson leader tells him he will be honored for his shrewd plan, once they've retaken their rightful world, but the scientist just wants the chance for revenge against the creature that ripped apart one of his faces.

The Decepticons are trying to get back to Cybertron's surface, but get lost. They come across the energy vampires, and Galvatron shoots them all down. However, they all get back up again, and lurch towards them.

Galvatron throws one of the remaining Sweeps at them, and they drain him of his energy. He then tells the other remaining Sweep to be a good solider and go and help him, as he throws him at the vampires. He then tells Cyclonus to hurry, as that won't stop them for long.

But the Dweller then appears, and catches Cyclonus. Cyclonus begs for help, as as Galvatron briefly hesitates, he says he has to get out of here, and runs off.

Meanwhile, the Autobots reach an exit shaft, but Arcee finds that it's rusted shut. As Magnus attempts to blow it apart, the Dweller crashes through a wall, forcing them to flee. They go around a corner and find Galvatron, who tells them he doesn't know what that thing is -but even if it gets him as well, he'll die with the satisfaction that the universe will have two more Autobots to mourn!

Magnus leaps forward and throws Galvatron back the way they came. As he gets up, the Dweller attacks him and knocks his cannon off of his arm. The Dweller starts to drain Galvatron of his energy, and also captures Magnus in another net.

Arcee picks up Galvatron's cannon, and uses it to repeatedly blast the creature, causing it to be sent flying through a wall. She goes to check on Magnus, who says he's weak, but can make it.

They see that the creature is moving toward the power core. They also see that Galvatron is down, but Magnus says they'll send the Junkions for him later, right now he's the least of their worries. They head back to the surface, as the energy vampires chase after them.

Perceptor tells Rodimus that some unknown force from beneath Cybertron's surface is absorbing energy like a sponge absorbs water. Rodimus see that whatever is doing it is on a direct course for the power core. Magnus and Arcee then make it back, and explain what's happened. Rodimus says they've got to destroy the Dweller before Cybertron becomes a dead husk, but then the energy vampires break down the door.

Perceptor says they're suffering from a unique form of energy depletion, making them into energy leeches themselves. Magnus asks what they can do about it, and Perceptor says a massive power load should bring their imbalance back to normal, and has the Autobots form a chain. He links up with a computer, sending energy through all of them, which hits the energy vampires.

The energy vampires are returned to their usual selves, although Cyclonus asks what happened. Springer says the Decepticons should tell them, but Scourge says to get out of here. The Decepticons leave by crashing out of a window.

They retreat from Cybertron, and Galvatron joins them. Galvatron says he has a score to settle with some deceitful Quintessons, but perhaps releasing that beast wasn't such a bad idea after all. On Cybertron, the Dweller arrives at the surface, and has grown to an enormous size. Perceptor says if it latches onto the power core, they'll be no stopping it. Rodimus says they'll have to get rid of the power core, by jettisoning the entire thing into space -it's the only way.

As the Dweller grabs the core, Perceptor pulls the lever, and the core blasts off with the Dweller still attached to it. Wreck-Gar tells him to not come back.

The Quintesson scientist finds it strange that they're nearing Cybertron, but he's still picking up energy readings. He thought the Dweller would have drained the planet completely by now. They then pick up something on the view screen, and wonder if it's an Autobot ship. The Quintesson leader wonders if it's an Autobot ship, but the scientist says it's metallic and organic combined. To his horror, he realizes it's the Dweller, which grabs onto their ship and drains it of energy.

Perceptor is able to get some emergency auxiliary power, and says that'll have to hold them until they can build a new power core. Arcee tells him that, considering that they're still here, and they got rid of that creature, it's a small price to pay...

NOTES

-The Secret Files segment for this episode is about the Decepticons.

-This episode was animated by Toei, and is one of their best looking episodes. The art is of good quality throughout the entire episode, and there are a few very nicely animated sequences, such as when Springer bursts out of the rubble, and the flashback showing the scientist getting one of his faces smashed apart by the Dweller. However, there is a rather famous coloring error in this episode:

When the Dweller arrives on the surface, a bunch of Autobots start firing at it. These are three of the Protectobots, but they are all given the wrong colors. From left to right, First Aid is colored as Eject, Streetwise is colored like Optimus Prime, and Groove is colored like Wheelie.

-This episode was also adapted into a comic book, but was never actually published. Scans of a few pages from it can be found here.