Things are shaking at Autobot HQ... and Ironhide believes it's that Decepticon junk punk Rumble is behind it. Spike points out the tremors are strongest on one side, so Ironhide runs a scan... but there are no signs of any Decepticons. However he has found something weird in there.

Sideswipe and Brawn knock down part of the wall, revealing a large cavern hidden behind it. The Autobots head in and explore it, and finds the bones of what appear to have been from some kind of giant creature. Spike explains that they're the fossilized bones of dinosaurs, the animals that ruled Earth millions of years ago. Wheeljack wants to know more about them.

Elsewhere, Soundwave and Reflector are doing some data gathering. They've gone to the hydroelectric power facility at the Great Falls, and return to the Decepticon HQ to report to Megatron. Meanwhile, Spike and Hound have arrived at a museum to find out more about dinosaurs.

Spikes shows Hound the complete skeletons for three different dinosaurs: a triceratops, a brontosaurus and a tyrannosaurus. Hound records data and then returns to the Autobot HQ with Spike. He creates holographic versions of the three dinosaurs, and Spikes says that the dinosaurs weren't very intelligent because of their tiny brains, but they were extremely powerful. Wheeljack wishes they had some dinosaurs working for them, as they'd really shake up the Decepticons. Ratchet agrees, and says they could build robot versions of these oversized iguanas... if it was OK with Optimus Prime.

Prime thinks robot dinosaurs might be useful, and gives them his authorization. Huffer thinks it'll never work and it's a big waste of time, but regardless, the Autobots start putting together their new dinosaur robots.

Having looked at the data Soundwave and Reflector have gathered, Megatron says there's a source that'll give them power to vanquish the Autobots and rule the universe, so they depart for the Great Falls. Meanwhile, Wheeljack and Ratchet gather together all of the Autobots. Wheeljack says he has great pleasure in introducing the Dinobots: Slag, Sludge and Grimlock!

Huffer runs up and laughs, he thought Wheeljack was meant to make dinosaurs! Ratchet tells the Dinobots to transform, so they do, revealing their alt modes for the first time. Prime is impressed, but asks what else can they do? Wheeljack and Ratchet order them to get rid of some debris, which they do by blowing it apart with lasers.

Wheeljack explains that the Dinobots have small brains, just like real dinosaurs. But they're working on improving... before he can finish, Ratchet alerts him to something. The Dinobots are going haywire! Slag charges at Ratchet, sending him flying across the room. Sludge is able to make several Autobots fall over just by stomping the ground a few times.

Soon Autobots are falling left and right. Grimlock stomps off to the control room and is followed by Bumblebee and Spike, who can only watch as the Dinobot attacks Teletraan I, blowing it up!

Ratchet arrives and sees what's happened. Spike gets out of Bumblebee, whilst Bumblebee asks Grimlock to try taking on a bug. Grimlock takes him up on his challenge and starts following him out of the control room. Ratchet goes to Teletraan I and tells Spike he's got work to do. Meanwhile, Slag and Sludge use their fire breath...

...but they can't get through Trailbreaker's force field. Prime has had enough and declares that the Dinobots must be destroyed, but Wheeljack asks him to wait -maybe his magnetic inducer can stop them.

Wheeljack runs up to the Dinobots and fires on them, and there is a bright flash of yellow light. Once the light fades, the Dinobots transform back to their robot modes and fall down. Wheeljack begs Prime to not make him pull the plug on them. Prime apologizes, but says the Dinobots must never be activated again, as they're too dangerous.

The Dinobots are placed in the cavern, which the Autobots then seal up. Meanwhile, the Decepticons arrive at the power facility, and quickly send the security there running. Inside, two workers notice the Decepticons, and know they need help in a big way. One of them attempts to send a message to Teletraan I, but there's no response.

With Teletraan I out of commission, Hound is sent out to check up on Decepticon activity. He and Spike are driving around when he picks up some electronic signals, and thinks it could be Decepticons. He pinpoints their location to the Great Falls, and contacts Optimus Prime. Prime acknowledges him and tells the Autobots to roll out, but also instructs Bumblebee to stay behind and guard their HQ.

At the facility, the Decepticons are hard at work filling up energon cubes. Outside, Megatron tells Starscream they'll have endless energy, but Starscream mentions that the Autobots could stop them. Megatron tells him he has a plan to deal with them, if they're foolish enough to show up. The Autobots do show up moments later, but Prime can't detect any sign of the Decepticons.

Hound says the signals are stronger than ever, and Megatron then appears. He orders his forces to attack, and they quickly reveal themselves and take on the Autobots.

Megatron hangs back and hooks his fusion cannon up to the facility's generators. He fires a super powerful shot up at where the Autobots are, which breaks apart the ground they are on and sends them plummeting below.

They land in the water and are carried off by the current. Spike, who had kept away from the battle, sees them fall just as Bumblebee arrives. He asks what he's doing here as Prime told him to stay at HQ, and whilst Bumblebee says he doesn't like to disobey, he had to do something. He hopes Optimus won't be mad, but Spike tells him he won't be anything unless they get some help. Starscream asks what they're going to do next, as he doesn't think a little bath will have finished the Autobots. Megatron says they'll retrieve their short circuited carcasses and prepare them for permanent dysfunction.

Bumblebee and Spike return to Autobot HQ and fill Ratchet and Wheeljack in. Spike wants to save Prime and their friends, but Ratchet says they don't have enough Autobots to fight all of the Decepticons. Wheeljack says they do have something else... he's been working on a little research project, a batch of memory components that will upgrade the Dinobot's brains. They should make them smarter and easier to control... he hopes. Bumblebee says Prime said the Dinobots must never be activated again, but Wheeljack asks if he has any better ideas. As they have no other choice, they get to work and install the devices into each of the Dinobots.

The Dinobots are reactivated, and Wheeljack commands them to go and save their Autobot friends, and their leader, Optimus Prime. Do they understand? The Dinobots speak for the first time, in a primitive manner, but they think they maybe should go and save their friends. Grimlock says they'll do as they're told... for now. He blasts down part of the cavern, creating a new exit that he and the other Dinobots fly out of.

Back at the Great Falls, the Autobots have been captured and are restrained with energon chains. Megatron tells them not to waste their energy, as they'll never break them in their weakened condition. He tells the other Decepticons to terminate them, but just before they can fire, they notice some Autobots flying towards them. Slag sees them and wonders which ones are their friends. Sludge points at the Autobot symbol on his chest and says it's the ones who have this face on them... he thinks.

Slag says that's good enough for him, and is the first to fire. The Dinobots lands and the Decepticons have no idea who these new guys are, but Megatron says they'll be scrap metal once they're finished with them. Before Megatron can fire, Wheeljack shoots at him with a special shot...

...which hits and causes him to fall. Megatron realizes he's been hit with a gyro-inhibitor, which has destabilized his equilibrium. As Megatron has fallen, Starscream tells the Decepticons that he's the new leader, and orders them to follow him. He transforms and takes to the air, firing several missiles at Grimlock. The missiles explode around him, but he's not effected, and fires back.

Slag takes down Thundercracker, whilst Rumble tries to topple Sludge. But Sludge stomps the ground, causing a mini-quake of his own that breaks Rumble down.

Skywarp attacks with some heat seeking missiles, only to be chomped on by Grimlock and tossed aside. Megatron recovers and says he'll lead them to victory yet, and transforms. He attaches himself to Starscream, and starts firing wildly. Meanwhile Wheeljack finds his friend's weapons, and picks up a couple of them.

He uses Sideswipe's flare gun to dry off the captured Autobot's circuits, whilst Bluestreak's bolts will give them all an instant recharge! The Autobots are freed, just as Megatron is separated from Starscream. Megatron transforms back and lands, and says they must retreat. The battered Decepticons pull out.

Bumblebee goes up to Prime and admits they disobeyed his orders, and Wheeljack says they deserve whatever punishment he has in mind. Spike tells Prime that if they had obeyed his orders, they'd all be goners by now. Prime agrees and says sometimes even the wisest men and machines can be in error, so he has no reprimand for Wheeljack or Bumblebee. And the Dinobots have proven their value, so will remain among them. The Autobots cheer as the Dinobots transform and roar.

NOTES

-SCRIPT DIFFERENCES: Click here for details.

-It's the Dinobots! There's just 3 of them at the moment, but a couple more will be introduced a few episodes from now. This episode was first broadcast in 1984, but the toys for them weren't available in 1985, and they'd become some of the most popular characters in the series, especially Grimlock.

-Wheeljack's lights that come on when he talks are orange in this episode, as they were in this one. They were blue before this, and will be back to blue in future episodes.

-I won't usually mention errors here, but this episode has a fairly famous one: when the Autobots are first shown chained up, Optimus Prime's chest is colored blue instead of red.

-Megatron does something a bit out of the ordinary in this episode: he transforms without shrinking! Usually he always shrinks down, but not this time. It looks bit awkward when he attaches to the bottom of Starscream's jet mode though.