Summoned by a signal from one of his bravest warriors, Optimus Prime thunders down from the skies above Earth and races into battle, his protoform body tracing a fiery path across the sky. Most powerful among the Autobots, he is dedicated to the recovery of the Allspark. Scanning an Earth truck, he morphs into a form that will allow him to hide until the time comes to enter battle against Megatron.