Chadwick Boseman and Sienna Miller star in a scene from the movie "21 Bridges." The Catholic News Service classification is L — limited adult audience, films whose problematic content many adults would find troubling. The Motion Picture Association of America rating is R — restricted. Under 17 requires accompanying parent or adult guardian. (CNS photo/STXfilms)
Chadwick Boseman and Sienna Miller star in a scene from the movie "21 Bridges." The Catholic News Service classification is L — limited adult audience, films whose problematic content many adults would find troubling. The Motion Picture Association of America rating is R — restricted. Under 17 requires accompanying parent or adult guardian. (CNS photo/STXfilms)
NEW YORK (CNS) — The harshly violent crime drama "21 Bridges" (STX) never explores the many themes it hints at raising.

There's a vengeful — or so we're told -- police detective, Andre (Chadwick Boseman), who has for years tried to avenge the death of his father in the line of duty by a shoot-'em-up approach to encountering criminals. He's fond of intoning observations such as "Justice comes at a cost."

At Dad's funeral, shown in flashback, the priest cites the warning to evildoers about those in authority in St. Paul's Epistle to the Romans: "He does not bear God's sword in vain."

There are also two mercilessly violent bad guys, Michael (Stephan James) and Ray (Taylor Kitsch), both of whom, like Andre, have suffered from missing fathers. Andre is among those on their trail after a major drug theft, with hundreds of kilos of cocaine, ends with the grisly deaths of eight police officers among the carloads who show up to investigate what they thought was a break-in.

In the pursuit, Andre has to decide whether his search for justice should be tempered with mercy.

As for Capt. McKenna (J.K. Simmons) and detective Frankie (Sienna Miller), are either of them the righteous figures they appear to be? Or have they made their own accommodations with dark bargains?

Most of the plot, in the classic film-noir style, takes place over a single night as police seal off Manhattan after figuring out that the cop-killers have neither means nor motivation to get very far without their payoffs. Potential egress consists of 21 bridges and tunnels, hence the title.

Then, Andre declares, "we flood the island with blue."

Director Brian Kirk and screenwriters Adam Mervis and Matthew Michael Carnahan never let this promising structure produce much in the way of surprise -- or even reflection. Once a character has served a tiny piece of the plot, death by gunfire follows swiftly. The resultant high body count and splatter factor as well as the numbing drumbeat of foul dialogue necessitate a restrictive classification.

Taut pacing, in this case, is no cover for failed aspirations.

The film contains pervasive gun violence with some gore and relentless rough and crude language. The Catholic News Service classification is L -- limited adult audience, films whose problematic content many adults would find troubling. The Motion Picture Association of America rating is R -- restricted. Under 17 requires accompanying parent or adult guardian.