Five years have passed since the final battle between the Autobots and the Decepticons left Chicago in ruins and claimed the lives of over a thousand civilians. The U.S. government has severed its ties with the Autobots and branded them as fugitives. An elite CIA unit called "Cemetery Wind" is formed by Harold Attinger with the intent of hunting down and exterminating the surviving Autobots with the aid of Lockdown, a Transformer bounty hunter. Meanwhile, using data obtained from destroyed Transformers, business tycoon Joshua Joyce and his technology firm Kinetic Solutions Incorporated (KSI) have discovered "Transformium", the molecularly unstable metal that is the lifeblood of Transformers. Joshua's prized creation is Galvatron, a Transformer created from the data inside Megatron's severed head.
In rural Texas, struggling robotics inventor Cade Yeager and his friend Lucas Flannery purchase an old Marmon 97 semi-truck in hopes of stripping it down and selling the parts to get Cade's daughter Tessa into college. Cade discovers that the truck is an injured Optimus Prime, and it is not long before Lockdown and Cemetery Wind operatives led by James Savoy storm into the Yeager's farm and threaten them. Optimus comes out of hiding to fend off against the operatives while Cade, Tessa, and Lucas are rescued by Tessa's boyfriend Shane Dyson, an Irish rally racer. They lose the operatives in a lengthy chase in Paris, Texas, but Lucas is killed by Lockdown's grenade during their escape. Using a drone he took during the raid, Cade discovers that the operatives and KSI are working together. Optimus rallies the remaining Autobots - Bumblebee, Hound, Drift, and Crosshairs - and travel with their new human allies to infiltrate KSI's headquarters in Chicago. There, Cade, Shane, and Bumblebee discover the firm's reverse engineering of Transformer technology. Upon discovering that Ratchet has been slain and his head is being melted down, Optimus and the Autobots storm into the headquarters to destroy the laboratory, but Joshua convinces them that their actions are futile.
As the Autobots leave the premises, Joshua launches KSI's prototype Transformers Galvatron and Stinger. Optimus and Galvatron engage in a grueling battle where Optimus realizes that Galvatron is Megatron in a new body. Suddenly, Optimus is blasted from behind by Lockdown, and in the midst of the chaos, he and Tessa are captured into Lockdown's ship. Aboard the ship, Lockdown explains to Optimus that the Transformers were created by a mysterious alien race known as the "Creators", which hired him to capture the Autobot leader. As a reward for Optimus' capture, Attinger's operatives are given the "Seed", a powerful relic that cyber-forms any wide area of land. Cade, Shane and the Autobots storm into the ship to rescue Optimus and Tessa; while Bumblebee, Crosshairs and the humans escape and crash into Downtown Chicago, the other Autobots detach the rear section of the ship before it leaves into space. Joshua and his business partners Su Yueming and Darcy Tyril retreat to Beijing, where Attinger hands Joshua the Seed in exchange for a stake in KSI control. The Autobots and their human allies follow them to prevent them from detonating the Seed.
At KSI's Beijing factory, Galvatron suddenly activates by himself and infects all 50 of the firm's prototype Transformers to do his bidding. Realizing the folly of his creations, Joshua betrays Attinger before he, Yueming, and Darcy take the Seed to Hong Kong. There, the Autobots struggle to protect Joshua and the Seed from Galvatron and his minions, which shoot down the Autobots' ship. Cade kills Savoy during a fight in an apartment building. Outnumbered and outmatched, Optimus Prime releases a group of legendary knights and leads them back to the city to destroy Galvatron's army. Lockdown returns to Earth and uses a magnetic weapon to pull vehicles under his ship and drop them on the Autobots. Optimus destroys the weapon and engages in battle with Lockdown before killing Attinger to save Cade. Lockdown grabs Optimus's sword and impales him, but the combined efforts of Bumblebee, Cade, Tessa, and Shane distract the bounty hunter before Optimus stabs him in the heart and slices his head in half. Galvatron retreats, vowing to battle Optimus another day. With Lockdown destroyed and Cemetery Wind dissolved, Optimus sets the Dinobots free before flying into space with the Seed, sending a message to the Creators.
Following the devastating events of Chicago in Dark of the Moon (film), humanity no longer trusts the Autobots and forces them underground in an attempt to wipe them out entirely. Government officials led by an arrogant engineer named Joshua have created their own robots and spaceships similar to Transformers in because of the discovery of a metal which they carbonize and galvanize in an attempt to replace them. Some of these transformers are Stinger and Galvatron.
Four years later, a single father and mechanic named Cade Yeager purchases a rusty old truck so that he may scrap it and sell its parts to obtain enough money to send his daughter Tessa to college. When the truck seems unable to be scrapped, Cade opens the front door and discovers gigantic bullet casings in the front seat. After hearing strange sounds after hooking it up to an electric circuit, he soon realizes that he has stumbled upon a lobotomized yet alive Autobot - Optimus Prime.
Not long after, a paranoid government official who leads the charge against the Autobots sends several of his men and Galvatron to kill Cade, Tessa, and Tessa's boyfriend Shane so they may recover Optimus. Just then, Optimus springs to life, defeats the humans, and takes the three to safety. But soon a robot named Lockdown captures Tessa and Optimus Prime who was fighting Galvatron.
The man-made transformers become sentient. Now it's up to Cade, Tessa, and Shane to ally themselves with the Autobots and defeat humanity's greatest failure.
- Mark Wahlberg as Cade Yeager, a single father and struggling inventor.
- Nicola Peltz as Tessa Yeager, Cade's daughter.
- Jack Reynor as Shane Dyson, Tessa's boyfriend and a race car driver.
- Kelsey Grammer as Harold Attinger, a CIA operative, founder of Cemetery Wind and the main antagonist.
- Stanley Tucci as Joshua Joyce, an arrogant designer who wants to build his own robots.
- Sophia Myles as Darcy, Joshua's geologist assistant.
- T. J. Miller as Lucas Flannery, Cade's best friend and a mechanic.
- Titus Welliver as James Savoy, leader of Cemetery Wind and hired by Attinger.
- Li Bingbing as Su Yueming, the "CEO of the Chinese Transformers".
- Victoria Summer as Joshua’s executive assistant.
- Peter Cullen voices Optimus Prime, the leader of the Autobots who transforms into a rusty Marmon 97 cab-over truck, and later a 2014 Western Star 4900 Phantom custom semi-trailer truck.
- Bumblebee, an Autobot who takes the vehicle form of a modified 1967 Camaro and later a 2015 Chevrolet Camaro concept.
- Mark Ryan voices Lockdown, a bounty hunter who is neither Autobot nor Decepticon. He transforms into a Lamborghini Aventador LP 700-4 Coupe.
- Robert Foxworth voices Ratchet, an Autobot who transforms into a green 2004 Hummer H2 Ambulance.
- John Goodman voices Hound, an Autobot who transforms into a 2005 Oshkosh Defense Medium Tactical Vehicle.
- John DiMaggio voices Crosshairs, an Autobot who transforms into a green 2014 Chevrolet C7 Corvette Stingray.
- Ken Watanabe voices Drift, an Autobot who was a former Decepticon tactician. He is a triple-changer who transforms into a black and blue 2013 Bugatti Veyron Grand Sport Vitesse and a helicopter.
- Reno Wilson voices Brains, a former Decepticon turned Autobot who survived the events of Transformers: Dark of the Moon. He transforms into a Lenovo ThinkPad.
- Leadfoot, an Autobot-Wrecker who transforms into a heavily armored and weaponized red Chevrolet Impala.
- Grimlock, a Dinobot who transforms into a Tyrannosaurus Rex.
- Scorn, a Dinobot who transforms into a Spinosaurus.
- Slug, a Dinobot who transforms into a Triceratops.
- Strafe, a Dinobot who transforms into a two-headed Pteranodon.
- Frank Welker voices Galvatron, the new Decepticon Overlord and the reincarnation of Megatron who transforms into a black and grey 2014 Freightliner Argosy cab over trailer truck.
- Stinger, a Decepticon who transforms into a red and black 2013 Pagani Huayra
- Junkheap, a Decepticon who transforms into a green Chinese garbage truck of Waste Management, Inc.
- Traxes (different colored Chevrolet Trax cars in the movie filming, they have blades in their arms), Decepticon soliders created by KSI controlled by Galvatron
Like its predecessors, it was directed by Michael Bay and written by Ehren Kruger, with Steven Spielberg and Bay as executive producers. It stars Mark Wahlberg, with Peter Cullen reprising his role as the voice of Optimus Prime, as the lead roles. It is the first film in the series to not feature the original human characters from the first three films, but features a new cast of human characters and many new Transformers, including the Dinobots. Returning Transformers include Optimus Prime, Bumblebee, Ratchet, Leadfoot, Brains and Megatron (now known as Galvatron). The film was released on June 27, 2014, in IMAX and 3D.
Transformers: Age of Extinction was panned by critics, many of whom considered it overlong, poorly acted, and badly written. According to Rotten Tomatoes, it is the worst reviewed film in the series. It also received seven nominations at the 35th Golden Raspberry Awards, including Worst Picture and Worst Prequel, Remake, Rip-off or Sequel, with Bay and Kelsey Grammer winning the awards for Worst Director and Worst Supporting Actor respectively. However, many praised the visual effects, the action sequences, Steve Jablonsky's musical score, and the performances of Wahlberg, Grammer and Tucci. Despite the poor reviews, the film was a major box office success. The film grossed over $1.104 billion worldwide, making it the highest-grossing film of 2014, the second highest-grossing film in the Transformers series, the 19th film to gross over $1 billion, and the 16th highest-grossing film of all time. It was the only film to gross over $1 billion in 2014.