It's the fifth instalment in the heavy-metal machine series and Optimus Prime has gone AWOL. The shape-shifting robots are arriving on Earth in increasing numbers to be met with resistance from the Transformers Reaction Force. Meanwhile, inventor Cade Yeager (Mark Wahlberg) hooks up with an English lord (Anthony Hopkins) and a voluptuous Oxford don (Laura Haddock) to thwart Megatron's diabolical plan to drain Earth of all life. Fans of over-sized, antagonistic mecha-beings are well rewarded with another all-action blitz on the senses.
Who would have thought that toy vehicles that can transform themselves into robots would spawn a clanking five-movie franchise and box office money-spinner?
Yet, since 2007, gung-ho Hollywood despot Michael Bay has been cranking out the heavy metal leviathans with little let-up in the lack of subtlety, humourless comedy and flag-waving Uncle Sammery.
This promises to be the last in the current franchise - they's only so many times you can seemingly stare into the workings of a Japanese motorbike misfiring on full throttle and then voice any desire for more.
It kicks off in familiar style. Robot good guy Optimus Prime is now inertly drifting through space, leaving the Earth as a battleground between the Decepticons (led by red-eyed Megatron) and a macho, S.W.A.T-style team known as the Transformers Reaction Force.
Out in the desert, widowed inventor Cade Yeager (whose name is a Bay speciality, sounding both ludicrous and noble at the same time), played by Mark Wahlberg, is hiding a small band of good guy Autobots, including Optimus Prime's lieutenant Bumblebee, in a sand-blasted scrap-yard.
We've also learned that an earlier iteration of the Transformers aided King Arthur 1,600 years earlier (who knew?), a revelation sketched out in a scene where you pray the Cockney-geezerish pitched battle mayhem was intentional but secretly doubt that it was.
This leads Cade to crusty Brit astronomer Sir Edmond Burton (Anthony Hopkins channelling The Fast Show's Ron Manager) who explains - laboriously - that the secret to stopping Megatron and his evil mistress lies with unlikely University professor Viviana Wembley (Haddock, playing her as an Oxford don who moonlights at Spearmint Rhino).
Yet these UK-set scenes - where Burton's C3PO-style, sociopathic butler-bot Corman (lugubriously voiced by Jim Carter) mutates into a silver Aston Martin DB11 - lift the movie when it is threatening to become a grind of never-ending scraps and ground-shaking rucks between miffed robots.
As you'd expect from Bay, there are a few dodgy decisions (whoever thought that shooting a WWII scene where Churchill's ancestral home Blenheim Palace is draped in swastikas should be taken out and shot).
Yet, it bowls along amusingly enough to a CGI maelstrom of a climax where you never experience a shred of peril yet have to grudgingly admire a director happy to throw all of his (Hasbro) toys out of the pram in the service of a wham-bang conclusion.