Somewhere in a bar, as the hands on the clock struggle toward closing time, there’s a half-drunken, almost Talmudic argument raging about which “Transformers” movie is the worst. “Transformers: Revenge of the Fallen”? “Transformers: Age of Extinction”? “Transformers: Dark of the Moon”? Some wise guy might even claim it’s the original live-action “Transformers,” without which the others wouldn’t exist.

Each side, armed with enough facts to make the health-care debate look simple, has a solid case.

Now, director Michael Bay has solved this conundrum of almost quantum-theory proportions that has bedeviled moviegoers since the first “Transformers” sequel in 2009. Like Moses coming down from the mountain, he has bestowed upon us the answer: “Transformers: The Last Knight,” a movie that is at once loud yet incoherent, complex yet idiotic, and expensive yet worthless.

Of course, complaining about a “Transformers” movie is like griping about gravity. What’s the point? But even by the standards of other “Transformers” movies (a couple of them certainly had their pleasures), “The Last Knight” falls far short, disrespecting the canon of the original story so much that even die-hard fans should rebel.

The incomprehensible plot has Mark Wahlberg returning as Cade Yeager, working-class hero and friend of the good-guy Autobots, who’s now in hiding with his robot pals. Autobot leader Optimus Prime (voice of Peter Cullen) is gone and humanity has become a plaything for a variety of metal men and our government is at war with them. The no-good Decepticons, the Autobots’ sworn enemy, are running amok though a few military guys, including Col. Lennox (Josh Duhamel), are doing their best to fight back.

Meanwhile, a magic staff given to man by the Transformers back in the Dark Ages — actually given to Merlin (Stanley Tucci, obviously doing this for the paycheck), who used it to help King Arthur — is now what’s needed to bring the Transformers’ dying home world of Cybertron back to life. (After “King Arthur: Legend of the Sword,” this is the second movie this summer to desecrate the memory of poor King Arthur.)

With a dizzying, byzantine story that bounces from the Dark Ages to contemporary Cuba (hey, John Turturro, what are you doing here? Oh, that’s right, collecting a paycheck, too) to contemporary England (et tu, Anthony Hopkins?), and Cybertron, “The Last Knight” doesn’t make a lick of sense.

That would be OK if it were any fun. But the jokes — the would-be humorous camaraderie with Yeager and his robot running buddies — are stale and unfunny. Some of the 3D visual effects, despite the reported bank-breaking $260 million budget, look surprisingly cheesy.

The multiracial, multinational crew Cade leads to save the world — teenage Latina tough-girl Izabella (Isabela Moner), African-American comic-relief Jimmy (Jerrod Carmichael from “The Carmichael Show”), brainy British scientist Vivian Wembley (Laura Haddock) — feels like a studied ripoff of every other big-budget movie these days where family is where you find it, not whom you’re born to. “The Fast and the Furious,” “Guardians of the Galaxy” and “X-Men” franchises and the “Star Wars” reboots have already plowed this territory far more effectively. Not content with that level of mimicry, Bay even throws in his own “cute,” R2-D2-like Transformer and a C-3PO wanna-be.

But the worst sin, if you’re an old-school Transformers fan, is how Bay — working from a script credited to Art Marcum, Matt Holloway and Ken Nolan all — has envisioned the Quintessons, the ancient race who created the Transformers in the first place. In the original lore, they were the most intriguing creatures in this universe, sly and sadistic, five-faced beings who brought a level of psychological complexity to a Hasbro-inspired toy-marketing enterprise that didn’t really deserve it. Their presence raised the question: if the Autobots’ makers are this twisted, can the Autobots themselves not be made of similar stuff?

But Bay has turned the Quintessons into a singular being, Quintessa (Gemma Chan), who is just some evil, generic, one-dimensional overlord who wants her magic staff back.

It’s the final nail in a coffin in a franchise that should be buried but won’t be. A spinoff with Hailee Steinfeld is due next year and “Transformers 7” is coming in 2019.

But, for now though, the argument is over and the bar is closed.

“TRANSFORMERS: THE LAST KNIGHT”

Rated PG-13

Now playing

One star (out of four)