Every January Hollywood releases mostly third-rate action vehicles that have been sitting on the shelf awhile. “Broken City” appears to be an excuse to get Mark Wahlberg fans flocking to the cinema during a time when the Oscar-nominated indie pics are the main attraction. Surprisingly, though, it is a watchable thriller packed with endless twists that eventually work themselves out–the story as a whole doesn’t make much sense until the denouement–and wry performances from Russell Crowe, Barry Pepper and Jeffrey Wright.

Wahlberg stars as a cop turned two-bit private eye after a scandal involving his shooting of an exonerated rapist and murderer. Now dating the victim’s sister (Natalie Martinez), a glamorous cinema upstart, he’s barely scraping by, unable to collect monthly payments from sleazy customers whose dirty assignments get him plenty roughed up. One day a call comes from the fabulously corrupt mayor (Crowe), the very same man who called for Wahlberg’s resignation, who pays him a princely sum to track down his wife’s (Catherine Zeta-Jones) lover. The deeply conservative mayor is facing fierce competition from a liberal golden boy (Pepper), who relentlessly attacks Crowe’s backing of a housing project’s lucrative privatization. News about the adultery will only sink Crowe’s campaign further.

Predictably, Crowe lies about the purpose of the assignment; Pepper’s campaign manager (Kyle Chandler), who may or may not be Zeta’s lover, is murdered; and a slew of people who work for Crowe privately plan his undoing. Meanwhile, Wahlberg gets himself into several deadly scrapes trying to uncover the mayor’s wrongdoing.

“Broken City” has its share of flaws. Several of the characters are ciphers, especially the political foes: Crowe is a foul-mouthed, New York Post-loving capitalist pig; Pepper is the umpteenth rich Wasp turned left-wing politico. While all of the major characters are not quite who they seem, Pepper’s, strangely, is meant to be taken at face value; there’s no slimy secret agenda behind his pandering populism. Wright is appropriately sly as the police commissioner, but the character is unfocused, veering from stern authority figure to Deep Throatesque informant and back again. And Wahlberg’s tortured detective remains an angry blank; we don’t buy that this average tough guy has the moral outrage to so fully sacrifice himself at the end.

But the film is swiftly-paced and the fight scenes are gritty and mean. The twists are enjoyably nutty even if they’re drawn from cliches. And some of the smaller scenes are gems. Martinez’s film premiere, where Wahlberg must watch her in a graphic simulated sex scene–leading to his falling off the wagon–is a hoot. And there’s a sassy turn from Alona Tal as Wahlberg’s cute assistant.

Director Allen Hughes makes some odd choices that, unexplainable as they are, nonetheless help drum up tension. On a final note: I’ve never seen more close-ups of stubble on-screen: we get a trip through Griffin Dunne’s pores as he shaves in a gym bathroom, and a little later there’s a virtual X-ray of Wahlberg’s glistening five o’clock shadow as he stews in a bathtub.