The Earth is attacked by unknown forces. As people everywhere watch the world's great cities fall, Los Angeles becomes the last stand for mankind in a battle no one expected. It's up to a Marine staff sergeant and his new platoon to draw a line in the sand as they take on an enemy unlike any they've ever encountered before.

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.