For his third outing behind the camera, former bad-boy actor Sean Penn displays a maturing confidence and narrative ease. He also flexes his growing directorial clout with the caliber of actors he’s able to bring to a project. Not only does “The Pledge” reunite Penn with Jack Nicholson (who starred in Penn’s last work “The Crossing Guard”), it also gives him a chance to direct up-and-comers Benecio Del Toro (“Traffic”) and Aaron Eckhart (“Erin Brokovich”). If only Penn’s choice of material — the mutilation and murder of a little girl — weren’t so grim. Although “The Pledge” explores emotional themes similar to both Penn’s “The Indian Runner” and “The Crossing Guard,” it hews more closely to the latter. Like that film, “The Pledge” hinges on the aftermath of murder. Despite being released by a major studio, “The Pledge” maintains a distinctly indie flavor and feel, which adds to the movie’s intrigue factor. “The Pledge” also enjoys the equally distinct advantage of not being based on a screenplay penned by Penn. The source material for this character-driven thriller about a retired detective’s lengthy search for a serial killer happens to be a 1958 novel by Swiss mystery writer Friedrich Durrenmatt. Mining foreign novels from the ’50s appears to be the current trend in Hollywood, triggered by “The Talented Mr. Ripley.” For whatever reason, the studio folks who greenlight those derivative teen romances and LCD (lowest-common-denominator) comedies seem unwilling to risk funding anything remotely original for more discerning adult audiences. Although “The Pledge’s” police procedural plot structure will be second-nature to most viewers, it does allow Nicholson’s burned-out former Reno detective the chance to go head-to-head with a slew of informants and suspects, all played by terrific actors in often single-scene cameos. There’s also a moral weight to the movie — stemming from the “pledge” of the title — that underscores the plot and Nicholson’s character’s fate with a tragic irony not usually found in crime drama whodunits. The movie begins at the retirement party for detective Jerry Black (Nicholson), who seems to be well-liked and respected by his colleagues. The festivities are interrupted, however, with word of a dreadful discovery: the bloody body of a local girl. The cops quickly track down the perpetrator, a mentally challenged Native American (Del Toro) with a long criminal record, who confesses. But while the hotshot young detective (Eckhart) is busy congratulating himself, Jerry remains unconvinced. Promising the young girl’s mother (Patricia Clarkson) on his “soul’s salvation” to find the killer, Jerry slowly becomes obsessed with solving the crime. As his investigation broadens, Jerry interviews classmates, the dead girl’s grandmother (Vanessa Redgrave), the father of a long-missing little girl (Mickey Rourke), and a macho cop (Michael O’Keefe) who solved a similar crime. Jerry begins to believe he’s tracking a serial killer who preys on blond little girls in red dresses. This brings him to roadhouse waitress Lori (Robin Wright Penn) who has such daughter. And a far-fetched plan to snare the killer. Decidedly downbeat and dark, “The Pledge” would be only a minor blip on the year’s box-office radar without the incredible performance by Nicholson. Showing an unusual subtlety and restraint, Nicholson traps us with his gradually telling peeks at a man driven by a mission so obviously above and beyond his capabilities. He’s also quite endearing when his character begins to realize that after two failed marriages, he’s actually falling into a mutually gratifying relationship with Lori and her daughter. While Penn focuses much of the movie on Nicholson’s interpretation of method acting, he doesn’t allow the star any opportunity for his usual big-scene, emotional, verbal outbursts. Instead, Penn keeps Nicholson on a tight leash; and a reined-in Nicholson is the perfect demeanor for Jerry. A low-key study in obsession and the power of one’s own instincts, “The Pledge” never quite rises above its prevailing dark mood and off-putting subject. While one can mentally appreciate the talented cast and artful look of the picture, when the lights come up, emotionally, one cannot help but be depressed.