Picking up two years after the Egypt incident, the Autobots and their human allies discover a lost piece of Cybertronian technology which has been in human possession for several years. It is revealed that the artifact is part of an Autobot spacecraft which has crashed on the moon during the Apollo 11 mission to the Moon and carries a special technology and the legendary Sentinel Prime (Optimus Prime's old mentor). However, Sam Witwicky discovers a conspiracy by the Decepticons who plot to use it for their own evil purposes. And Optimus Prime finds that they are up against a menace who plans to also use it to enslave humanity in order to restore Cybertron.