Out in deep space, Astrotrain is ferrying Megatron, Starscream and Rumble to parts unknown, where they stumble upon an interesting sight: A planet with the Autobot insignia! Curious yet cautious, they land and start searching, finding the place to be completely empty and find themselves before a tower with ancient Autobot text written on it.
Starscream fiddles with a control device and
happens to get it reactivated, generating a hologram with a message of warning:
Leave now, or they will never return to Cybertron alive, for they will rust and
wither away. Megatron believes it to be just a trick to scare them away and they
explore further, expecting treasure of some sort.
It doesn't take long before they happen across a Lightning Bug and they set about trying to activate it, which in Starscream's case involves humping it. Megatron gets it working and makes it blast a hole in the ceiling, and is all too pleased with this discovery; a weapon the Autobots created and abandoned, which he can now use to destroy them himself!
They take the Lightning Bug and leave the
planet, but they soon find that an asteroid is on their tail! Megatron gives it
a dose of the Lightning Bug's power, destroying it into mere shards...
That begin penetrating Astrotrain's hull. Megatron gets one embedded in his shoulder, badly wounded by it and urges Astrotrain to speed up their return to Earth.
Upon arriving, Astrotrain is revealed to be out of commission for weeks until he's fixed, but Megatron claims he's the one who needs attention.
Starscream performs the very delicate operation of yanking the shard out with a giant claw, disappointed that the procedure was successful. Megatron examines his wound and finds it coated with something very odd: Rust! After all, the Transformers are rust-proof, but Starscream jokes that his leader was made of shoddy materials.
Meanwhile at the National Scientific Achievement fair, Perceptor is being congratulated for the invention of corrostop, a solution that resists rust and corrosion and is stronger than any known metal. The Autobots plan to coat an Earth monuments with it, but only have enough to do one of them, and since it's made from a rare element they wouldn't want it discovered by the Decepticons.
With a statement like that, you just know that's precisely what will happen, but not yet, surprisingly! Megatron says to Starscream that replacing his chest won't be enough to stop the rust, and demands the Stunticons be called in to kidnap Perceptor and see if he can solve his problem.
Meanwhile, the Autobots and Aerialbots are overseeing the coating of the Statue of Liberty.
But on a nearby cruise ship, the Stunticons
are on board! With a few threatening words, they lock the passengers behind a
shutter and they've successfully taken over the boat. They arrive on the shore
where Perceptor is being interviewed and after using some laser fire to chase
him around, Motormaster nabs him with a chain lasso.
As you do when you're being kidnapped by
renegade sports cars with bad attitudes, Perceptor calls for help, but the
Autobots are too busy just admiring their fine coating work rather than checking
on the guy they need to protect from bad guys. Thankfully, the interviewer
informs Prime about the situation, and the Aerialbots are dispatched to sort it
The Stunticons shove Perceptor aboard Blitzwing and blast off through the city, the Aerialbots tracking him to the best of their ability. The Decepticons arrive near the undersea headquarters but don't land just yet, calling Dirge and Ramjet out to make use of the Lightning Bug.
Air Raid and Fireflight are hit badly by the Lightning Bug, singeing their wings and leaves them unable to fight back, allowing Blitzwing to land and get away with Perceptor. The Aerialbots are given no choice but to return to base and inform Prime.
Perceptor is brought before Megatron, who greets him politely only for the Autobot scientist to berate him on being kind even though they're mortal enemies and
All witnessing are appalled at the sight, but Megatron gets straight to business: He wants Perceptor to help cure him of this rust plague, and in return he will have peace. He complies to his demands, and begins examining him, seeing he's covered in a rare metallic plague that legend says had destroyed large civilisations many years ago, much like the robot equivalent of the Black Plague. Cosmic Rust!
He examines things further, seeing that the asteroid shard is covered in Cosmic Rust germs, and they're feeding off the Lightning Bug's energy to spread and expand faster. While ranting and raving about wanting a cure, Megatron's hand falls off, but Perceptor applies a sprinkle of corrostop and it's good as new, which the Decepticon leader applies to the rest of his body.
Meanwhile in space, Cosmos laments to Blaster that there is no more Element X, which is news that'll apparently make Prime rather unhappy. In Autobot Headquarters, Megatron calls Optimus and asks if they want Perceptor back; obviously they do, but he explains that they've got until noon to do so...
For Perceptor is trapped in his alternate mode and placed in a valley, where the afternoon sun will focus through his lens and ignite the fuse of the bomb it's aimed at! Prime rallies the Autobots and informs them that it's pretty obvious they're moving into a trap, but for the sake of Perceptor it's pretty much essential, even though it means that they'll be on the Decepticons' turf.
They arrive and see no sign of the villains, so Prime sets to releasing Perceptor, but the scientist tells him not to or else he will be infected with Cosmic Rust, but his leader just orders him to shut his trap as he saves him from the bomb. He continues to ask to be left behind for fear of infecting everyone else, though they go uncared for and he's dragged back to headquarters whether he likes it or not.
Perceptor tries to tell them about the germs, but Wheeljack just uses Teletraan-1 to find out more about it. The Cosmic Rust germs originated from a planet named Antilla, which Autobots led a thriving civilisation on at the dawn of time, but asteroids with the germs rained pain upon them and decimated the place. No cure was found.
They can't make any more corrostop without Element X, but Wheeljack suggests they use the matter duplicator to make more, even though it never worked in the first place. Prime tries to get more info from Teletraan-1, but finds that his hands are covered in the germs and have made the machine non-functional, and only now do the rest of the guys realise they're infected too.
Megatron is sitting outside the Ark with the Lightning Bug, using it's power to speed up the death process for his enemies. The Autobots manage to see this on Teletraan-1 somehow despite being broken less than a minute ago, so they decide that the matter duplicator is their only chance. And by giving it a good kicking, it manages to work!
In Decepticon HQ, Soundwave returns with Laserbeak's visuals of what's going on inside the Ark, allowing Megatron to laugh at his enemies stumbling around like zombies and being really under the weather. However, it's recorded Perceptor alerting the others of the matter duplicator success, so all they need to do is get some corrostop from the Statue of Liberty and they can duplicate it! The Decepticons decide to head there as well.
They arrive along with the Stunticons, who merge into Menasor and are commanded to blast the Statue of Liberty with the Lightning Bug. However, the Autobots are waiting for them and open fire after a few snappy quips, resulting in a fire fight.
Before Menasor can actually do anything with the Lightning Bug, the Aerialbots arrive and merge into Superion, knocking the Decepticon down a few times before splitting him into their component parts. Victorious, Superion blasts the Lightning Bug, leaving the Decepticons to beat feet.
Prime believes they've seen the last of Cosmic Rust, which Bumblebee agrees with and is also pleased with the fact they saved a lady at the same time. Everyone's confused until he says it's Lady Liberty herself. Everybody cheers because go America!
Astrotrain quite simply vanishes after they return to Earth, and after being told to fetch the Stunticons Starscream doesn't do anything else, though he is seen in one shot or two.
The Stunticons still own their cruise ship when they arrive at Lady Liberty.
I'd like to complain about the Autobots not doing anything to get it back to it's rightful owner, but then I remembered they're kind of being eaten by Cosmic Rust. Priorities.