The "Transformers" film series is about the ongoing battle between the Autobots and the Decepticons, warring factions of Transformers from the planet Cybertron. Their battle takes place on Earth, with many humans becoming caught in the crossfire during the struggle.
As of Nov. 5, 2015, there have been four installments in the "Transformers" series. The first three, "Transformers," "Transformers: Revenge of the Fallen" and "Transformers: Dark of the Moon," focus on Sam Witwicky, played by Shia LaBeouf. Sam unwittingly becomes involved in the war between Autobots and Decepticons when he purchases a car that is revealed to be Bumblebee, an Autobot. Bumblebee puts Sam in contact with Optimus Prime, leader of the Autobots, so Sam can contribute to the defeat of the villainous Decepticons. "Dark of the Moon," the third installment, ends with the Decepticons seemingly defeated.
The fourth installment, "Transformers: Age of Extinction," introduces a new cast and storyline. Cade Yeager, a mechanic played by Mark Wahlberg, accidentally discovers Optimus Prime in hiding. Yeager allies with Optimus Prime to stop humans intent on exploiting the Transformers, such as Joshua Joyce, a businessman played by Stanley Tucci, and Harold Attinger, a paranoid CIA agent played by Kelsey Grammer. A fifth installment in the series, set to directly follow "Age of Extinction," is set for release in 2017.