Four million years ago the Autobots and Decepticons crash-landed on Earth and went into stasis. In the present, Bumblebee wakes up first and learns from Ratchet that a volcanic eruption has already revived the Decepticons. A chain of missions follows — energon raids, battles with Soundwave and the Seekers, a defection by Jetfire — culminating in a trap on Cybertron where Shockwave has ruled unchallenged in the Autobots' absence. The final confrontation at Shockwave's fortress goes badly until Grimlock arrives and ends it with his teeth.