It’s too long and entirely too damned glib about the ultraviolent mayhem it unleashes on the just and the unjust.

The plot is intentionally convoluted, with “hero” assassins and a disapproving Fed out to save a lady assassin from the the child trafficking murderers who made her.

Yes, that sounds suspiciously like the plot to John Wick meets the “Ballerina.”

And that effete, nerdy autistic accent Ben Affleck slings in his return as “The Accountant” is…a choice. As the character is on the autism spectrum, one wonders if this is Health and Human Services Secretary Brain Worm approved.

But Affleck and Jon Bernthal click as assassin brothers who reunite for “The Accountant 2,” a bloody-minded, firearm and fusillade filled line-dancing buddy comedy version of “Sound of Freedom.”

Director Gavin O’Connor (“Warrior”) also returns from the 2016 film and just steamrolls through logical lapses and other shortcomings in a film that ultimately amuses and never spares the mayhem. Give all involved their due. This beast plays and satisfies. And how.

Our not-entirely-humorless on-the-spectrum savant is living a lonely life in Idaho, desperate enough to change that by enlisting in a speed dating event, still too practical to give up living in an Airstream trailer, which doesn’t impress all the single ladies…of Boise, but does have room for a lot of guns.

Chrisian Wolff gives the appearance of an accounting assassin who has all but retired.

But the murder of his retired former Federal contact (J.K. Simmons) in the film’s opening scene sends Federal Financial Crimes Enforement Network (a real Federal agency…for now) deputy director Medina (Cynthia Addai-Robinson, also returning to the sequel) in search of answers about what her former colleague was digging into that had him magic marker “Find The Accountant” on his arm as one of his last living acts.

Reaching out to a school full of autistic “savants” like Wolff, supported by Wolff, brings The Accountant to Medina. And he lets her know that getting to the bloody bottom of what appears to be a human trafficking case run by a murderous lowlife (Robert Morgan) who can afford to hire whole teams of contract killers will require help.

First, they’ll need to use The Accountant’s unseen Brit (Alison Wright) and their version of Xavier’s School for Gifted Youngsters’ crack team of teen hackers. And Wolff will require the assistance of his slightly less awkward, just-as-murderous brother Braxton (Bernthal) to finish this dirty, off-the-books, high-body-count job.

The school for gifted, on-the-spectrum hacker kids is an inspired invention, a deus ex machina of competitive, mostly-silent teens and tweens who can break into any electronic system, invade any privacy and manipulate devices and people to find out anything, steal any selfie, track any person or device.

But the master stroke here is promoting Bernthal to co-star. He’s antic to Affleck’s shy and reserved, giving Brax a big-spending, high-living, lolipop-sucking swagger in opposition to brother Chris’s baggy dad pants and practical wind breaker jackets.

Brax is amoral and annoying, shrugging off torture and killing their way to answers in ways the Fed never abides.

“Were you dropped on your head as a child?”

He gets under his brother’s skin like the never-grew-up-adolescent he remains, mimicking Chris the way he probably has since he was eight and Chris was 10.

“Don’t repeat me!”

“Don’t REPEAT me!”

Their chemistry together rarely feels forced, even when autistic Chris decides, on impulse, to learn country music line-dancing.

Our chilly Debbie Harry-meets-Florence Pugh Latina assassin (Daniela Pineda) is mainly just a dye-job, haircut and dead-eyed look of feigned disinterest in people and violence stolen from a whole series of Luc Besson lady-“cleaner” thrillers.

But her big fight delivers, and even the over-the-top slaughter of the film’s finale has a saving grace. It’s set up by a lovely gut-punch moment with no words in which the remote-control teen savant hackers realize what flesh-and-blood bad guys do to children.

Whatever the “puzzle” all involved must figure out, whatever the good guys do that’s as bad as the bad guys, “Accountant 2” trots along on the backs of Affleck, freed to be “funny” in the part, and Bernthal, whose bluff and ebulient presence gives him that freedom.

It’s not particularly ambitious and there’s barely a hint of “breaks from formula” in it. But in “The Accountant 2,” it’s not the individual numbers that matter. It’s how it all adds up.

Rating: R, graphic violence, imperiled children, profanity

Cast: Ben Affleck, Jon Bernthal, Cynthia Addai-Robinson, Daniela Pineda, Grant Harvey, Robert Morgan and J.K. Simmons.

Credits: Directed by Gavin O’Connor, scripted by Bill Dubuque. An MGM/Amazon release of a Warner Bros. film.

Running time: 2:04