(USATODAY.com) - The Autobots are flexing serious muscle and new weapons in Transformers: Age of Extinction, the fourth installment in the Michael Bay-directed live-action franchise.
Optimus Prime and Bumblebee took plenty of knocks in the third episode, 2011's Transformers: Dark of the Moon. But the computer-generated pair quickly return to form in the new flick opening June 27.
They ''are bigger and badder-ass than they have ever been," says Lorenzo di Bonaventura, who has produced all four films, with Steven Spielberg and Bay as executive producers.
Bay says the "new chapter" required refreshing the look. "A lot of people are like, 'What does that mean, Transformers 4?' It's like Batman with a new suit. We needed to change the look from top to bottom."
Extinction is set three years after the devastating Battle of Chicago from the third film. There is a new location (Texas) and cast. Shia LaBeouf, the human anchor in the first three films, is gone.
Instead, Mark Wahlberg arrives as single father and cash-poor inventor Cade Yeager. Yeager and his daughter (Nicola Peltz), her young boyfriend (Jack Reynor) and comedic sidekick Lucas (T.J. Miller) get caught up in the Transformer world when Yeager buys a bullet-riddled truck to repair. He doesn't know it's actually Optimus Prime in hiding.
Optimus Prime goes from junkyard shabby to wielding a new power sword in no time.
"The sword is emblematic of what we've done to Optimus Prime as a whole," says Di Bonaventura. "He's been upgraded with more abilities."
Bumblebee takes his martial arts to another level with Chinese star-style adornments on his armor. The two also have new souped-up transformation vehicles. Optimus Prime eventually reveals himself "like a knight in shining armor" as an impressive Great Western truck, says Di Bonaventura. Bumblebee re-emerges as a new souped-up Camaro. Yellow, naturally.
There are plenty of new Autobots as well, including ones voiced by John Goodman (Autobot Hound) and Ken Watanabe (Drift).
The upgrades continue with the introduction of Dinobots, ancient creatures who enter the franchise "with their fists and feet first," says Di Bonaventura.
The biggest difference in Extinction is that humans are fearful and less trusting of both heroic Autobots and evil Decepticons since the Transformer destruction of the last film. After devoting himself to protecting humans, Optimus Prime turns hard and cynical about this human betrayal.
This is especially apparent when government forces led by Harold Attinger (Kelsey Grammer and Savoy (Titus Welliver) attack him at Yeager's farm. But he never loses his Transformer heart.
"There are changes, but he still maintains the element of characters that are so important to him," says Peter Cullen, who has voiced Optimus Prime in each movie since 2007's Transformers and in the 1984-1987 TV series. "Since the original concept of Optimus Prime, the trustworthiness, the honor, the courage are still there. That will always prevail. And that's the basis of his popularity."