On the run in the year of 1987, Bumblebee finds refuge in a junkyard in a small Californian beach town. Charlie, on the cusp of turning 18 and trying to find her place in the world, discovers Bumblebee, battle-scarred and broken.

Humans are at war with the Transformers, and Optimus Prime is gone. The key to saving the future lies buried in the secrets of the past and the hidden history of Transformers on Earth. Now, it's up to the unlikely alliance of inventor Cade Yeager, Bumblebee, an English lord and an Oxford professor to save the world.