Optimus Prime and the Autobots team up with a down on his luck young man, an aspiring historian and with a powerful faction of Transformers known as the Maximals to combat a sinister force from outer space that threatens the Earth and all of mankind.
On the run in the year 1987, Bumblebee the Autobot seeks refuge in a junkyard in a small California seaside town. Charlie, about to turn 18 and trying to find his place in the world, soon discovers Bumblebee, broken and battle-scarred. When Charlie revives him, he quickly realizes that this is no ordinary yellow Volkswagen.
The humans are at war with the Transformers and Optimus Prime is gone. The key to saving the future is 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 gentleman, and an Oxford professor to save the world.
After an epic battle, a great city lies in ruins, but the Earth itself is saved. As humanity begins to pick up the pieces, a dark group emerges to try to take control of history. Meanwhile, an ancient and powerful new threat sets its sights on Earth. A new group of humans, led by Cade Yeager, help Optimus Prime and the Autobots face their most fearsome challenge yet, a global war of good versus evil.
Sam and his new girlfriend Carly join the fray as the Decepticons renew their long war against the Autobots. Optimus Prime believes that resurrecting the former Transformer Sentinel Prime, who was once the leader of the Autobots, can lead to victory. That decision, however, has devastating consequences, as the war seems to tip in the Decepticons' favor, leading to a climactic battle in Chicago.
Two years after Sam and his Autobot friends saved Earth from the Decepticons, Sam Witwicky faces a new battle: college. Meanwhile, Optimus Prime and the Autobots are working with a secret military organization and trying to make a home for themselves on Earth. When a former Decepticon known as The Fallen rises up for revenge. Sam and his girlfriend, Mikaela, must uncover the history of the Transformers on Earth and find a way to defeat The Fallen once and for all.
The fate of humanity hangs in the balance when two robot races, the Autobots and the Decepticons, take their war to Earth. The robots have the ability to transform into different mechanical objects while searching for the key to ultimate power. Only a young man named Sam Witwicky can save the world from total destruction.