There was the uninspiring “Bounce” of 2000 with Gwyneth Paltrow. Then, the train wreck that was “Gigli,” with Jennifer Lopez. Later, the “rom-com” swill that was “Jersey Girl,” which starred J. Lo again.

However, Ben Affleck “bounced” back, and this time he has chosen a mighty fine script to work with—Dennis Lehane’s novel “Gone Baby Gone”—and an impressive cast of actors.

While he remains behind the cameras as director of “Gone Baby Gone,” a crime thriller about a 4-year-old missing girl and her drug-addicted mother, his casting and artistic decisions allow the film to shine with gritty Bostonian authenticity.

With younger brother Casey Affleck playing the lead of rookie private investigator Patrick Kenzie, stellar Morgan Freeman as head of the police department’s Crimes Against Children Unit and the intense Ed Harris as a long-time police officer, “Gone Baby Gone” is an ambitious look at the underbelly of Boston’s crime circles.

In short, an uneducated, cracked-out mother—played brilliantly by Broadway actress Amy Ryan—leaves her innocent, sleeping daughter in bed at their Dorchester home as she heads to a local bar. The Dorchester neighborhood is a tough one, mostly lower working class, dotted with slummy bars where drug-related shootings are a regular occurrence.

Little Amanda McCready goes missing while her negligent mother is out, and the police seem unable to unearth any leads. The young girl’s aunt insists on hiring Kenzie and his girlfriend Angie, who know the city and its murky depths, to gather clues on Amanda’s disappearance from the neighborhood’s seediest residents.

As the pair dives into the Bostonian underworld, piecing together information supplied by anyone from bartenders to addicts, the noir-esque plot gathers speed.

Patrick continues to collect more information on Amanda’s whereabouts, submerging himself in the city’s bowels of crime and struggling with his own sense of “right” and “wrong.” The intentionally confusing—and mostly unexpected—ending fuels the urban “food for thought” vibe Ben Affleck presumably set out to accomplish.

Although the screenplay’s writing, artfully crafted by Ben Affleck and Aaron Stockard, is mostly cogent and convincing, the film’s first 30 minutes seems utterly desperate to convince the audience of its understanding of the city. Reminiscent of a Dashiell Hammett or Raymond Chandler hardboiled novel, but with a less clear-cut and more moralistic ending, “Gone Baby Gone” covers an immense amount of plot work in one hour and 54 minutes—a somewhat short film in light of recent years’ mammoth three-hour movies.

Despite these flaws, Ben Affleck’s feature directorial debut and Casey Affleck’s emergence as a true leading man rely heavily on the elder brother’s excellent execution of casting.

Ben Affleck hired Ryan, a Queens native, on the spot at her audition, and the actress seized the role with street-smart panache by spending time in Boston bars and with locals hired as extras.

In fact, at one point, according to a New York Daily News profile of the actress, after she got into costume and proceeded to walk around the Dorchester neighborhood to prepare for her next scene, Boston cops would not allow her to cross back over the filming barricades, mistaking her for a local.

It is this informed casting, supplemented by the actors’ superb performances and Ben Affleck’s guiding directorial hand, that make up for an at times implausibly complicated story in “Gone Baby Gone.”