The race for the Cyber Planet keys draws powerful allies to both sides as the stakes are raised. Megatron's forces have the Autobots under pressure, while Starscream attains unprecedented size and power. The Autobots fight back when deep secrets from Cybertron's past reveal the true form of their home: Transformer creator, Primus. The final battle is joined as Optimus Prime faces Megatron, revived as the unstoppable Galvatron!