Spoiler:
Sari takes the Autobots to "Dino Drive", a dinosaur exibit, in order to teach the Autobots some of Earth's history. On the way, Bulkhead accidentally destroys every car in the parking lot. Once inside, the see the dinosaurs and become amazed by the dinosaurs' power. Bulkhead becomes so fascinated he tries to get the Pteranodon to fly and do other things to amuse him. This only succeeds in having the robot Pteranodon fall and cause a Triceratops and Tyrannosaurus robot to collide and break each other. With this, the Autobot take the broken animatronics to Professor Sumdac for repair.At the lab, Megatron views the power of dinosaurs through the Tutor Bot and becomes amazed at their apparent strength. Sumdac then walks in and realizes the Tutor Bot is on and becomes perplexed at how simple the information on it is, saying how everyone already knows it. Megatron then speaks to him, saying he did not know. Sumdac becomes shocked at Megatron's awakening and tells him where he is. Megatron the reassures him that since he's not going anywhere, he can sit through a long story. Megatron then convinces Sumdac that he is a friend of the Autobots and that they'll be happy to see him repaired so they keep his existence a secret. He tells Sumdac he will help him repair the dinosaurs, not revealing that he plans on using them for prototype attack drones.
Meanwhile, at the Autobot base, Prowl tries to teach Bulkhead how to control his strength and size. This, of course, ends with Bulkhead falling on Prowl. He then takes him to an abandoned island to train, but this results in Bulkhead dropping trees onto Prowl.
At the Dino Drive, Sumdac reveals his and Megatron's creations—the Dinobots!
After displaying what Sumdac programmed to do, Megatron makes them display what he programmed them to do—destroy the Autobots! As the Dinobots attack them, Bulkhead tries to recreate Prowl's teaching, but no effect as the others get beat up by the Dinobots. Ratchet and Bumblebee then combine their powers to create an electromagnetic pulse to shut them down, but Sari's key activates to blow the dinosaur skin off them and reveal their robot bodies. Sumdac then takes them back to his lab to see what he can fix.
At his lab, Megatron becomes perplexed as to why the key activated, thinking something was Cybertronian about the Dinobots. He then dismisses this idea and curses the drones for being useless. Then something happens that surprises Megatron—the Tyrannosaurus starts to talk, and the other dinosaurs to to move! And on top of that, he finds he can't control them!
Megatron then surmises that the Autobots did something to them, declaring, somehow, they have sparks of their own. The Tyrannosaurus then dubs himself "Grimlock" and, without fail, Megatron declares that he is the Dinobots' leader. Grimlock doesn't approve of this concept and announces that he is the leader. The Tutor Bot activates, much to Megatron's annoyance, and explains how dinosaur fossils make fossil fuel which makes cars and trucks work. Grimlock takes this as that cars and trucks "eat" dinosaurs and announce that cars and trucks are bad. Megatron takes advantage of their low intelligence and tells them that "fossil feeders" are bad and the only thing worse then cars or trucks are car robots, aka Autobots. He then causes them to activate their fire breath powers and they use them to destroy the Tutor Bot. Grimlock is pleased with this, but does not know how he did it. Megatron then tells them that the fossil feeders want them dead, so the Dinobots go to defend themselves.
As they go to wage war on the fossil feeders, Captain Fanzone arrives to attempt to stop them. Suddenly, Slag (who has not yet named himself, neither has Swoop) whips a car with his tail and Capt Fanzone's car becomes the first causality of the Dinobots' war on the fossil feeders as the thrown car lands on it. Fanzone then takes a bazooka and shoots Slag, but Slag just eats the missile.
The Autobots then arrive and lure them to a park to battle them. As Grimlock sees them transform, he says he forgot something but then remembers that he was told that car robots were worse than cars and trucks. As the battle goes on, the Autobots are seriously outmatched, especially since Bulkhead is trying to "access the situation" as Prowl tried to teach him to do. Prowl, realizing the disadvantage they're in, hollers for Bulkhead to not try and be like Prowl, but to be like Bulkhead. Reassured, Bulkhead quickly downs Slag and Swoop.
Meanwhile, Bumblebee and Ratchet are pinned down by Grimlock's fire-breath. Slag and Swoop get up and join in, the heat melting the parking lot behind the two Autobots. Optimus remembers the tar lesson from Dino Drive, and Bulkhead throws the Dinobots into the newly formed pool. The Dinobots use their flames in an attempt to free themselves from the "black-sticky-stuff", but only make things worse for themselves.
The Dinobots are trapped with only their heads sticking out. With the chunk of lot cooled, forming a prison, the block is extracted so the Dinobots can be removed. Sumdac promises to melt them down due to their danger to society. Optimus approves of this, but Prowl does not, feeling that they have sparks within them. As Sumdac returns the next morning, he finds the Dinobots have escaped from their tar prison.
On the deserted island where Prowl and Bulkhead trained on, the Dinobots are freed into a large crater, which houses a beautiful natural environment. Prowl and Bulkhead then see how happy they are and decide to keep it their secret. With that, Prowl sets a hologram up to keep them hidden and safe from the world.
After they leave, Grimlock dubs cars and trucks bad, but nature good. Two birds promptly defecate on him which makes him retake his claim and dub them stupid. He orders them to come down and fight like a Dinobot.
Suddenly, Grimlock transforms! Slag and Swoop stare in amazement as Grimlock draws his flaming sword. Grimlock approves of this.