Microbots
Megatron has obtained a new super energy component, the "Heart of Cybertron," from the crashed Decepticon ship. It is violently unstable, and could explode catastrophically at any time. Perceptor, Brawn and Bumblebee are shrunk to micro size to sneak into Megatron's body (he's "drunk" at the time) and retrieve the component. The search is difficult, given Megatron's immune system, and the argument between Perceptor and Brawn of mind over power, but Perceptor finally earns Brawn's respect as the trio finds the component and manages to escape Megatron and shoot the self-destructing component just in time.