The movie “21 Bridges” opens with a bang. Not literally — it’s just a close-up of a 13-year-old boy’s tear-streaked face, as he listens to the off-camera sermon delivered at his father’s funeral. We learn that Dad, a New York City cop, has been killed in the line of duty, but not before he “punished” three of the four criminals he was pursuing.

It’s an artful — and telling — moment, not only for the image’s simplicity, emotional power and good casting. Playing Andre, the young actor Christian Isaiah really looks like he could grow up to be Chadwick Boseman, who later portrays NYPD detective Andre “Dre” Davis as a grown man. It also sets the stage for the rest of the overly schematic but reasonably watchable film, with the erroneous assumption that it’s the role of the police to not just enforce the law but to mete out harsh justice for those who break it.

Dre, of course, who is the film’s hero, doesn’t really believe that, but people think he does. The second scene in the film shows him in front of an Internal Affairs panel that is investigating his propensity for discharging his firearm on the job. And when eight cops and a civilian are killed in the robbery of a wine store with a freezer full of 300 kilos of cocaine — only 50 of which are actually taken — Dre’s presumptive trigger-happiness is what gets him assigned to the case by the captain of the precinct whose officers were gunned down (J.K. Simmons).

Dre, it is assumed, will find the perps and, you know, save us all the headache and heartache of endless appeals and plea bargains with a strategic bullet or two. He is assisted in the hunt by a DEA agent (Sienna Miller, with whom Boseman has an unfortunate lack of chemistry).

Ah, but chemistry — or, for that matter, character development — is not what “21 Bridges” is about. It is a game of hide-and-seek, as Dre quickly persuades the police brass and the FBI, who persuade the mayor, to shut down Manhattan: every bridge, tunnel, train track and river into and out of the city, for a window of a few short hours while he uses his almost superhuman deductive skills to tighten the noose around the perps. (Taylor Kitsch plays the cop killer, and Stephan James is his more reluctant — and less bloodthirsty — partner).

It’s a pretty artificial, not to mention absurd, scenario, as Dre goes after his quarry with speed and success that is surprising even for someone with his Sherlock Holmes-like forensic powers. Soon enough, it becomes apparent to him — and to us — that there is a setup going on, as he observes very early in the film.

It isn’t hard to figure out who’s behind it, if you’ve seen a million of these things.

And there have been a lot of them. “21 Bridges” will win no prizes for originality or twists. (It won’t win any prizes for anything, to be honest.) But it’s made well enough. Brothers Joe and Anthony Russo (“Avengers: Endgame”) are the producers, and Irish director Brian Kirk (“Game of Thrones”) knows how to keep an old jalopy like this well-oiled to get us across the finish line.

In other words, “21 Bridges” gets the job done. So does Boseman, who is satisfying to watch, even when he has little to do except the right thing. Dre isn’t tarnished or tainted in any way. He’s not guilt-ridden, seeking redemption or complicated. “21 Bridges” might be a teeny bit more interesting if he were.