During tremors, the Autobots find fossilized dinosaurs bones which brings an idea to Ratchet to build transformer dinosaurs: the Dinobots. Ratchet presents the Dinobots; Grimlock, Sludge and Slag to the Autobots, but the Dinobots get crazy and start destroying everything. The Autobots disconnects them and buried them in a cave.
At the Great Falls, the Decepticons have taken over and begun producing Energon cubes. The humans attempt to call the Autobots via Telatran-1, but it was destroyed by the Dinobots. Spike and Hound are out on patrol when they discover the Decepticon activity and go to report Optimus. The Autobots move out to fight the Decepticons. Ratchet, Wheeljack and Bumblebee are left behind to guard the base.
The Autobots are defeated by the Decepticons, thanks mostly to Megatron's super-powered Fusion Cannon. As Spike watches the Autobots imprisoned, Bumblebee shows up to help. Together, they go back and deliver the bad news to Wheeljack and Ratchet. Without any other options, Wheeljack installs brain upgrades into the Dinobots, making them (slightly) more intelligent and easier to control. They go to the rescue of the prisoner Autobots, defeating the Decepticons. In gratitude, the Dinobots can remain active among the Autobots.