Summoned by a signal from one of his bravest warriors, Optimus Prime thunders down through the space 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, and the protection of both the humans on Earth and his own people back on Cybertron. Scanning an Earth truck, he morphs into a form that will allow him to hide until the time comes to enter battle against Megatron!