Transformers: The Last Knight has a deeper mythos and bigger spectacle than its predecessors, yet still ends up being mostly hollow and cacophonous.
Following the events of Transformers: Age of Extinction, Optimus Prime (Peter Cullen) is still off in space, having set out in search of his Cybertronian Creators. Meanwhile, the Autobots (Bumblebee included) remain fugitives on Earth, along with their current human ally: the inventor Cade Yeager (Mark Wahlberg). Upon helping a group of kids who had inadvertently crossed paths with the Transformers Reaction Force - a global human organization that is dedicated to hunting and destroying Transformers of any affiliation - Cade ends up taking in Izabella (Isabela Moner), a young girl who was orphaned back during the Battle of Chicago. In the process of doing so, Cade crosses paths with an ancient, dying Transformer who then gives him a mysterious talisman.
It turns out said talisman has ties to not only the Transformers' secret history on Earth over the ages - as Cade learns from astronomer and historian, Sir Edmund Burton (Anthony Hopkins), the member of a society tasked with protecting those secrets - but the destinies of both Cade and one Viviane Wembly (Laura Haddock), a Professor at the University of Oxford. When Cybertron itself then mysteriously begins to approach the Earth, spurning the TRF to strike a bargain with Megatron (Frank Welker) and the Decepticons to protect our world, it falls to Cade and his Autobot friends to find the legendary technology that can save the planet, humanity and Transformers-kind alike, first.
While Transformers: The Last Knight is the fifth addition to the live-action Transformers movie franchise overall (as well as the fifth - and supposedly final - one directed by Michael Bay), it is the first installment to be plotted out by members of the Transformers writers group that was assembled by Paramount Pictures, back in 2015. The main goal of said writers group was to expand the Transformers movie franchise into a full-blown cinematic universe, with The Last Knight serving as both an entertaining continuation of the previous films and an intriguing "launching board" for future Transformers sequels and spinoffs. Sorry to say, The Last Knight is not all that successful at being either of those things. Transformers: The Last Knight has a deeper mythos and bigger spectacle than its predecessors, yet still ends up being mostly hollow and cacophonous.
The Last Knight, if nothing else, is a pure Michael Bay production from a technical perspective... in the sense that it prioritizes rapid-editing, explosion-fueled sequences and flashy set pieces over coherent action-driven storytelling. Working with John Wick cinematographer Jonathan Sela, Bay does bring a proper sense of grand blockbuster scale to The Last Knight with his camera angles and shot choices, as well as a dynamic sensibility to the proceedings in general. Problem is, Bay's IMAX 3D visual style hasn't evolved much since his efforts on the third Transformers movie, Dark of the Moon, and The Last Knight's technical flourishes come off as more derivative than engaging, in turn. The Last Knight may feature more shiny, computer-animated Transformers and non-stop spectacle than its predecessors, but Bay seems to be out of fresh ideas for what to do with this franchise, from an action filmmaking perspective. Even the unique settings of the movie's third act (and a Suicide Squad-inspired introduction to the Decepticons) only do so much to liven up the otherwise by-the-numbers Transformers battles on display.
Screenwriters Matt Holloway and Art Marcum (Iron Man) - working alongside Ken Nolan (Black Hawk Down) from a screen story by Akiva Goldsman (The Divergent Series: Insurgent) - stick closely to the Transformers movie narrative formula with their script work for The Last Knight, right down to including an easy-to-identify MacGuffin (here, Merlin's staff) to drive the story forward. The writing team does manage to fit a good deal of world-building (setting up the Transformers cinematic universe in the process) into the otherwise conventional three-act narrative here, without slowing things down in terms of the story flow. Problem is, because so much more time is spent on expanding the franchise mythology and calling back to the events of previous Transformers movies, The Last Knight fails to provide most of its human players with just basic arcs - something that even the prior installments were able to do. As for the central story threads in The Last Knight: they're somewhat incomprehensible, riddled with plot holes that are simply too large to ignore and carry half-formed political overtones, but that's par for the course for the Transformers franchise at this point.
Also par for the course for the Transformers movies is frequent crude humor and human characters who are more cartoonish stereotypes than three-dimensional individuals. The Last Knight doesn't change course in this respect either, giving rise to a number of ungainly tonal shifts and over the top comedy scenarios that clash with the movie's efforts to integrate more emotional plot beats and substantial character connections into the proceedings here. Mark Wahlberg's Cade Yeager shares the spotlight with two leads here - one a romantic interest in Laura Haddock's Viviane Wembly, the other a "replacement" daughter in Isabela Moner's Izabella - but his relationships with both characters fall flat, due to the lack of both onscreen development and chemistry between the actors. Even more so than the humans from Transformers movies past, the heroes in The Last Knight are one-note players who spend more time running and shouting exposition than interacting in meaningful ways.
The Last Knight features appearances by a handful of familiar faces from Transformers movies past (see, for example, Josh Duhamel as William Lennox), but these special cameos tend to feel superfluous to the movie and seem to exist to better make the Transformers franchise feel like a "universe", more than anything else. The most noteworthy newcomers here include Jerrod Carmichael as Cade's hired help Jimmy, as well as Anthony Hopkins as Sir Edmund Burton and his Transformers protector, Cogman (voiced by Jim Carter). Carmichael is stuck playing a stock comic relief type here, but there is fun to be had in watching the Oscar-winning Hopkins go full Looney Tunes mode in The Last Knight. Burton gets little more to do than provide exposition dumps and swear/crack juvenile jokes, but Hopkins seems to be enjoying himself in the role. As for Cogman: like the various returning Autobots, Decepticons and Dinobots in The Last Knight, he's a zany CGI character in a live-action world that tends to be grating to listen to, more than anything else.
In terms of the other Michael Bay-directed Transformers movies, The Last Knight is neither the solid popcorn movie that the first and third installments arguably are, nor is it quite as messy and slapdash as the second and fourth chapters (Revenge of the Fallen and Age of Extinction, respectively). If anything, the biggest issue with The Last Knight is that it fails to leave as strong an impression - either good or bad - as Bay's other Transformers movies have before it, despite being over-stuffed with mythology and big-budget fireworks. Fans of Bay's general approach to the Transformers franchise will naturally get the most traction out of the fifth chapter, but even some of the director's die-hard supporters may find themselves left feeling bored and numb by The Last Knight. Suffice it to say, it's for the best that Bay is stepping away from the franchise at last.