Hollywood is so obsessed with superhero movies these days it made one about a crusading accountant. It’s called The Accountant, and it is indeed about a guy who prepares people’s taxes, looks for deductions, and monitors financial records for fraud. But in his off-hours, this guy is also a master martial artist and a sniper capable of hitting targets from a mile away. He has a kind of sixth sense for never being properly photographed; every picture the government has of him is of the back or side of his head. He also has several secret identities and what amounts to a low-rent Batcave, an Airstream trailer full of weapons and cash, stashed in a storage unit. He’s played by former Daredevil and current Batman Ben Affleck. He doesn’t wear a cape, but he might as well.

That’s not to say the movie’s bad; at the very least, The Accountant has a bit more interesting stuff creeping around its edges than a lot of the superhero movies based on established properties. Ben Affleck stars as the man we first meet as Christian Wolff, who apparently shares his name with a famous German philosopher and mathematician. This is not a coincidence. It’s an alias; one of many this accountant has used for years to cover up his work as a money launderer. Though he operates out of a nondescript strip mall in suburban Illinois, the Accountant boasts an extraordinary clientele of international drug dealers and underworld types from around the world.

Hoping to get a break from immoral work, the Accountant accepts an assignment auditing the books of a robotics company led by a philanthropic tech magnate (John Lithgow). A low-level employee named Dana Cummings (Anna Kendrick) discovered a discrepancy in the company’s nearly indecipherable financial records, so the Accountant is brought in to pinpoint the issue. When Dana tried to figure out the problem on her own, she spent weeks on a single fiscal year. The Accountant identifies the culprit in 15 years of spreadsheets over the course of one inspirational montage of feverish scrawling on the walls and windows of a conference room. (Writing on walls or windows is movie code for “This person is very smart.” Smart people in movies are too smart to write on paper. It is beneath their intelligence.)

Warner Bros.

And the Accountant is very smart. In addition to his prowess with weapons and his fists, he also has what he describes as “high-functioning autism,” which gives him peerless dexterity with numbers, memorization, and computation. There are drawbacks — he struggles in social situations and failing to complete a task can send him into an emotional meltdown — but The Accountant treats this condition as a kind of real-world superpower. (A documentary about living with autism this is not.)

All of this is one layer of the movie; there are several others. There’s also a young Treasury Department agent (Cynthia Addai-Robinson) recruited by her unscrupulous boss (J.K. Simmons) to track down the Accountant. There’s another highly proficient underworld assassin (who does not, at least as far as we see, moonlight as a CPA) on the Accountant’s trail. He’s memorably played, in charming psychopath mode, by Jon Bernthal. And there are flashbacks to the Accountant’s childhood, mostly involving his disapproving and demanding Army officer father which operate as sort of origin story for this unusual antihero. Fans of director Gavin O’Connor’s movie Warrior may recognize some of the same themes in play here.

Affleck isn’t bad in the role — his emotionless delivery is funny at times, particularly playing off the bubbly Kendrick  — but his lengthy history as an action hero undermines the character. Everyone is so surprised that this bean counter is such an enormous badass. “He’s just an accountant!” two different people exclaim at various points of the movie. The shock of this guy being as deadly with a calculator as a Glock would land with a lot more oomph if the Accountant was played by, say, Michael Cera instead of the 6’4” dude with pecs the size of honey-glazed hams who’s anchoring the Justice League movie.

Warner Bros.

On the plus side, the movie’s action and fight scenes are better than average, with fluid choreography and intense violence. The benefit of putting Affleck and his robust physicality in this part is that he can clearly do a lot of his own stunt work, and the lack of cuts lends a lot of credibility to the sequences where he tears through legions of goons with alarming efficiency and many, many headshots. It’s sort of like John Wick meets a version of Good Will Hunting where Affleck and Matt Damon decided to switch roles.

From the very first scene, a bloody shootout in a mob stronghold that withholds the identity of the gunman, O’Connor hints at a twist on the horizon. That leads to a kind of a Schrödinger's cat scenario in The Accountant. The early scenes establish this weird funky world where accountants are world-class hitmen, robotics companies are havens for insidious malfeasance, and danger lurks around every corner. The world-building is engrossing. The premise is refreshingly peculiar. The action grabs your attention. As long as the movie keeps a lid on what precisely is going on, it works.

But then O’Connor starts opening his mystery box, and in just about every single case the reality of what’s inside fails to live up to the promise of the messy pile of puzzle pieces. In just about every single case, the surprises are also both obvious and preposterous, the worst possible combination. You don’t have to be a pattern-recognition genius like Christian Wolff to see these things coming.