In deep space, an object passes by two suns: Unicron. Unicron, a planet sized being, sets his sights on Lithone, a small planet.

On Lithone, two of its inhabitants, Kranix and Arblus, are going about their day as normal. Suddenly everything starts to shake, and they see that Unicron is heading straight towards their world. Unicron begins to attack the planet.

Using his pincers, he stabs into the planet itself, and starts to bring it towards him. Buildings everywhere are destroyed, as Kranix tells everyone to get to the ships -it's their only chance.

Kranix's group reach some ships, and take off. Meanwhile Lithone continues to be torn apart, as Unicron begins to consume it. Kranix and Arblus escape together in one ship...

...but another ship following them fails to escape Unicron's gravity, and gets sucked back in. Unicron consumes it and the rest of the planet, and converts everything into energy to power himself. With Lithone destroyed, Unicron continues on to his destination: Cybertron.

"It is the year 2005. The treacherous Decepticons have conquered the Autobot's home planet of Cybertron. But, from secret staging grounds on two of Cybertron's moons, the valiant Autobots prepare to retake their homeland..."

At Moonbase 1, a frustrated Ironhide asks Optimus Prime when they're going to start busting up Decepticons. Optimus tells him he wants him to make a special run to Autobot City on Earth -they don't have enough energon cubes to power a full scale assault. He then tells Ironhide to ready the shuttle for launch. As Ironhide heads off, none of the Autobots are aware that Laserbeak has been spying on them.

Optimus asks Jazz to report security status, and he says there's no sign of any Decepticons here. Jazz then contacts Moonbase 2, to find out if they've seen anything. On Moonbase 2, Bumblebee and Spike respond, and Bumblebee says everything is clear.

Spike tells Ironhide to tell his son, Daniel, that he misses him, and that he'll be coming home -as soon as they've kicked Megatron's tail across the galaxy. Optimus has Cliffjumper commence a countdown, and five seconds later, the shuttle takes off.

Optimus says that all they need now is a little energon... and a lot of luck. Laserbeak stops recording, and heads back to Cybertron. Megatron welcomes him, and says that unlike some of his other warriors, he never fails him.

Starscream hears that comment, but stays quiet. Megatron has Soundwave transform, so he can play back Laserbeak's findings. The Decepticons watch a video of Optimus ordering for the shuttle to launch, and how the Autobot leader thinks they'll need a lot of luck. Megatron says Prime will need more than he can imagine.

As the shuttle approaches Earth, the Autobots inside it hear an explosion. They look behind them and see Megatron tearing into the shuttle, followed by many Decepticons.

As the Decepticons enter, Brawn charges towards them. Megatron tells the Autobots to die, and transforms. Starscream fires him, and Brawn gets shot in the shoulder.

Brawn falls down and dies. Prowl gets up and fires back, but his shot misses. Scavenger returns fire...

...and his blast goes straight through Prowl, killing him. Ironhide and Ratchet, the two remaining Autobots, get up and open fire on the Decepticons.

But the Decepticons take cover and repeatedly shoot them. With the battle over, Megatron transforms and tells Starscream this was almost too easy. Starscream thinks it was easier than attacking the real threat -the Autobot's Moonbases. Megatron calls him an idiot.

He says that once they've slipped by the Autobot's early warning systems in this shuttle, and destroy Autobot City, the Autobots will be vanquished forever. Ironhide reveals he isn't dead yet and latches on to Megatron, but Megatron doesn't care for such heroic nonsense, and fires a fatal shot.

On Earth, Hot Rod and Daniel are fishing. Hot Rod asks Daniel what's wrong, and Daniel says he guesses he just misses his dad. Hot Rod tells him not to worry, as Spike will be back soon. Hot Rod then catches a fish, a pretty big one.

Daniel's computer then beeps, as he finds out the shuttle is coming. He wants to go and watch it land, and heads off. Hot Rod thinks that's dull, and tosses the fish back into the lake. Daniel gets on his hoverboard and heads out, whilst Hot Rod runs after him.

Daniel ends up hitting a rock which breaks his board and almost him, but Hot Rod catches him. Hot Rod tells him if he's going to ride, ride in style! He transforms to his vehicle mode. Daniel suggests they stop at the city, but Hot Rod asks why settle for a peak when you can see everything from Lookout Mountain.

Nearby, Kup is overseeing some other Autobots as they set up a roadblock, but Hot Rod smashes through it. As Hot Rod drives on, Kup tells the turbo-revvin' young punk that he'll straighten him out yet.

Hot Rod comes to a stop and lets Daniel out, as they see the shuttle coming in to land. Daniel uses some binoculars and notices something strange: there's a hole in the shuttle! Hot Rod zooms in and sees that some Decepticons are in it.

He starts firing at it, and Kup wonders what he's doing. Hot Rod's shots cause part of the shuttle to explode, forcing the Decepticons to abandon it. Megatron orders the Decepticons to attack, and fires at Hot Rod. Hot Rod grabs Daniel, as Megatron's shot destroys Lookout Mountain.

Hot Rod and Daniel land safely, but they are immediately confronted by Blitzwing and Shrapnel. Blitzwing tells the Autobrat to come on down, and transforms to his tank mode. He takes aim...

...but just before he fires, Kup appears, and pulls his turret up. His shot ends up striking Shrapnel, who then collides into him, and the two are knocked away.

Hot Rod tells Kup that wasn't bad for an old timer. Kup tells him "old timer" is something he'll never be if he doesn't get back to the city. The two are then attacked by Starscream, so they transform and head back. Inside Autobot City, Perceptor transforms and views the Decepticons heading towards them.

He transforms back and reports to Ultra Magnus that a cursory evaluation of Decepticon capabilities indicates a distinct tactical deficiency. In other words, Springer says, they're outnumbered. Magnus tells Springer and Arcee to transform Autobot City, whilst Perceptor is to tell Blaster to radio Prime for reinforcements. Blurr runs up and asks what he can do to help, and Magnus tells him to help him alert the others. Blurr says absolutely positively definitely -no one can get the job done faster than him!

Magnus, Blurr and Perceptor head out. Springer and Arcee are about to go, but Arcee says Hot Rod and Kup are still outside the city. Springer says they can't wait -they'll have to take care of themselves. He and Arcee then start using various controls, as the entire city begins to transform. As the two run down a trench, they come under fire...

...from Starscream, who tells them there's no escape. They manage to get away, and Starscream sees he's about to be trapped. He jumps up, but gets his foot stuck in between two closing panels.

He has no choice but to shoot himself to get free. Meanwhile, the city completes its transformation, revealing many weapons.

Megatron shoots at a door, but even he can't destroy it. He orders his forces to breach the Autobot's defenses, as Shrapnel and Kickback start eating their way through a door. Nearby, Kup says the Insecticons are in their way, but Hot Rod says they're their way in. He drives over Kickback, and knocks Shrapnel back.

Kup then runs over Kickback, and sends Shrapnel flying out of the way. The battle continues, as Autobot City comes under heavy fire.

Blaster is using a cannon, and shoots down Long Haul. He notices Perceptor, and asks him what's shakin' -other than this fortress. Perceptor tells him that Ultra Magnus sends orders to contact Optimus Prime on Moonbase 1. Blaster transforms, and puts out a distress signal to Prime -the Decepticons are blitzing Autobot City, and they don't know how much longer they can hold out.

As the Decepticons continue their attack, Megatron notices what Blaster is doing. He tells Soundwave to jam the transmission, so Soundwave sends out four of his cassettes: Rumble, Frenzy, Ravage and Ratbat.

The Decepticon cassettes transform and rip off the satellite dish. Rumble smashes his way through a window, as he and the others attack Perceptor. Perceptor tells Blaster to save himself.

Blaster says no way -two can play. He reveals his own cassettes, as he sends out Steeljaw, Ramhorn, Eject and Rewind. As they fight their Decepticon counterparts, Perceptor asks Blaster if he thinks he got through to Prime. Blaster says he hopes so -otherwise they're all going to look like burnt out toaster ovens.

As the battle continues, Megatron leads the Decepticons to a larger gun turret. Nearby, Arcee is moving some wounded Autobots aside, as Springer goes up to a missile launcher.

Windcharger and Wheeljack have fallen, but Springer tells Arcee that Megatron is making his big push -they've got to push back! Just then Kup, Hot Rod and Daniel show up, and they start moving the launcher into place. Arcee tells Hot Rod she was afraid he'd be trapped outside the city. Hot Rod says he wasn't worried for a micro-second, but Arcee thinks he probably didn't understand the situation.

Daniel tells Kup and Hot Rod to look at this. Kup goes up and sees that the Constructions are transforming into Devastator. Devastator walks up to the turret...

...and crushes it, before starting to punch down a wall. Springer loads the launcher and fires several missiles.

The missiles scatter most of the Decepticons, but Devastator is able to withstand them, and throws a large piece of metal at the Autobots. The Autobots have to abandon the launcher and run off. The battle continues throughout the night...

...and on into the morning. Megatron says the Autobot's defenses are broken, so let the slaughter begin. As Devastator tears through another door, Megatron notices something in the sky.

Another Autobot shuttle has arrived. Optimus Prime tells the Dinobots to destroy Devastator. Grimlock says he loves a challenge. He and the other Dinobots jump out, fly down towards the city and then transform.

However, Devastator notices them, and kicks Grimlock away. He then throws Sludge, but is unable to stop Slag, who tackles him into a wall.

Swoop dives in, but Devastator knocks down part of the wall to flatten him. As Optimus watches the Decepticons, he says that Megatron must be stopped -no matter the cost.

NOTES

-The movie is considerably darker than the TV series, as within the first few minutes there is a scene which features planetary genocide. There is then, of course, the biggest difference between the movie and the TV series: characters dying. For the movie -and for the movie only -the Decepticons outright kill several Autobots. In the series, characters would get injured all the time, but they'd always get repaired and pull through. Not the case here, however.

-The reason for this is because of the situation with the toys. The 1984 and 85 toys were mostly being pulled from store shelves, replaced with the new 1986 lineup. When faced with what to do with the old characters, the writers came up with an idea: kill them off. Hasbro, not caring about old product, were fine with allowing this to happen. Kids would surely be fine with watching their toy collections getting wiped out on screen, and having to buy the new toys... right?

-During Unicron's attack on Lithone, during this shot, there are several backgrounds featuring ruined buildings, seen on the left. They appear to be backgrounds from Fist of the North Star, a series animated by the same company who animated this movie: Toei.

-In an earlier draft of the script, Autobot City is the place where the Autobots create energon cubes, hence why Ironhide is sent there by Prime to collect cubes, and why Megatron wants to destroy it. Unfortunately this bit of info was cut from the final script.

-Speaking of which, it seems the Autobots now also use energon cubes -previously in the TV series, only the Decepticons were using these.

-One of the new Autobots is Arcee. Writer Ron Friedman has said in an interview that the idea of including a female Autobot as a permanent member of the main cast was met with heavy resistance by Hasbro. Ron wanted to include Arcee as his daughter was a fan of the TV series. Unfortunately, no Arcee toy was produced, despite a prototype being made.

-Oddly, only four of the Dinobots appear for the majority of the time: Grimlock, Slag, Sludge and Swoop. Snarl is mostly missing, but does appear briefly a couple of times.