An ancient struggle between two Cybertronian races, the heroic Autobots and the evil Decepticons, comes to Earth, with a clue to the ultimate power held by a teenager.
Sam Witwicky leaves the Autobots behind for a normal life. But when his mind is filled with cryptic symbols, the Decepticons target him and he is dragged back into the Transformers' war.
A deadly threat from Earth's history reappears and a hunt for a lost artifact takes place between Autobots and Decepticons, while Optimus Prime encounters his creator in space.