Director Kathryn Bigelow and screenwriter Mark Boal surprised prognosticators, critics, and regular audiences alike with 2009's "The Hurt Locker," a low-budget Iraqi War thriller that defied the odds (and relatively low box-office returns) to win the Best Picture Academy Award. For their follow-up, Bigelow and Boal have tackled a film both similar and diametrically opposite, one that also is set during the current war, but based around a much bigger hot-button topic: the search for, and killing of, Osama Bin Laden. Positioned as a juicy, step-by-step insider's procedural, "Zero Dark Thirty" is an altogether denser, more literate motion picture, hung with a serious clinician's eye and anchored by an exceptionally nuanced performance from Jessica Chastain (2011's "The Help"). One of the movie's clearest achievements is how plausible it is; without needing to stretch the truth, a riveting potboiler has been made, taking viewers behind powerful closed doors and into the line of fire as a meticulous investigation leads to the most famous manhunt in history.

Before a single image has been glimpsed, ghostly voices—actual recordings—of 9/11 victims seeking help while stranded in the World Trade Center fill the soundtrack. One woman pleads for her life as she huddles on the floor, the fire near her so hot she can barely stand it. "Please, God, I don't want to die!" she pleads. It's a chilling prologue, but also a necessary one, setting up the very reason why the people seen on the screen for the next two and a half hours have such a sacrificial desire and drive to find the person responsible and make him pay. Two years later at an undisclosed Black Site, young CIA analyst Maya (Jessica Chastain) sits in on her first military interrogation between partner Dan (Jason Clarke) and an Al Qaeda member (Reda Kateb) who is subsequently starked, humiliated and waterboarded for vital information. Eventually, he gives in and spouts out a name—Abu Ahmed al-Kuwaiti—who, as an alleged courier of bin Laden's, sends Maya and her team on a nearly eight-year-long wild goose chase of false leads, abrupt stops and unexpected breakthroughs.

"Zero Dark Thirty," which is a military reference to half past midnight, or the time when bin Laden's compound was raided on May 2, 2011, is dense, gritty, sumptuous, and free of superfluous melodrama. All the same, it is not ineffectual, with 2005's bus and tube bombing in London and 2008's attack on the Karachi Marriott depicted with a stunning, aggravated immediacy. Hitting even closer to home for Maya, who wavers between hard and vulnerable while not daring to reveal her true internal hang-ups and disdain, is a tragic breach of a thought-secured CIA base in Afghanistan, leading to the deaths of several of her colleagues. Amidst these events is, admittedly, a lot of exposition and hushed tones in darkened rooms, but it all contributes to the film's intrigue. There is something immensely gratifying with being made privy to the tireless work and maneuverings of the military and CIA, the viewer experiencing the jobs vicariously through the figures on screen. It helps, of course, that it is carried out with such seeming realness.

Jessica Chastain is destined to win much acclaim (and more than a few awards) for her stunning work as Maya, a fictionalized composite of some real-life CIA analysts screenwriter Mark Boal met with and learned about during his research. Not much is learned about Maya's past or her extracurricular activities, and that's on purpose; she has given up everything for her job, a fact that she refuses to acknowledge until she's met her goals. If Boal barely hints at breadcrumbs of information and back story, leave it to the chameloeonic Chastain to fill in the gaps with her sheer presence and depth as a person and performer. There isn't a weak spot in the ensemble surrounding her, each one fulfilling their duties as if they're not acting at all. This includes Jason Clarke (2012's "Lawless") and Jennifer Ehle (2011's "Contagion") as Maya's colleagues Dan and Jessica, and Chris Pratt (2012's "10 Years") as Justin, a Navy SEAL involved in eliminating bin Laden.

"Zero Dark Thirty" has a sleek look, courtesy of Greig Fraser's (2012's "Killing Them Softly") cinematography, and a cool, jittery score from Alexandre Desplat (2012's "Argo"). Taking its time before approaching the expected finale, if the meticulously researched nighttime showdown at Osama's hideout—a compound actually sitting in plain sight—teeters on the edge of anticlimactic only due to Bigelow's refusal to exploit the subject, then the final scene makes up for it with a much-earned outpouring of emotion. The entire film, as steely, direct and workmanlike as it's been, has culminated in this moment, one that powerfully pays off Jessica Chastain's dedicated, worn-thin Maya in a big way. It's a dramatic catharsis that arrives at precisely the right time, one that is crucial for "Zero Dark Thirty" to satisfy while leaving the permeating imprint that it does.