Young teenager Sam Witwicky becomes involved in the ancient struggle between two extraterrestrial factions of transforming robots – the heroic Autobots and the evil Decepticons. Sam holds the clue to unimaginable power and the Decepticons will stop at nothing to retrieve it.

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.

The Autobots continue to work for NEST, now no longer in secret. But after discovering a strange artifact during a mission in Chernobyl, it becomes apparent to Optimus Prime that the United States government has been less than forthright with them.

As humanity picks up the pieces after the battle of Chicago, a shadowy group reveals itself in an attempt to control the direction of history…while an ancient, powerful new menace sets Earth in its crosshairs. With help from Cade Yeager, Optimus Prime and the Autobots rise to meet their most fearsome challenge yet.

Humans and Transformers are at war. Optimus Prime is gone. The key to saving our future lies buried in the secrets of the past, in the hidden history of Transformers on Earth. Saving our world falls upon the shoulders of an unlikely alliance: Cade Yeager; Bumblebee; an English Lord; and an Oxford Professor.