After years of interrogating prisoners, deciphering lies, surviving bombs and avoiding bullets, Maya, the CIA agent played by the excellent Jessica Chastain in “Zero Dark Thirty,” is asked by a superior what she has done for the CIA other than hunt for Osama bin Laden.

“Nothing,” she says.

It is both lament and point of pride. She has devoted her life to tracking down America’s most wanted. Other than her job, we know almost nothing about her. It’s as if she were immaculately conceived to deliver the world from injustice.

But while it’s hard to connect to Maya and her struggles in the first half of “Zero Dark Thirty,” the result of her painfully long investigation pays off in a stunning nighttime raid of Osama bin Laden’s compound in Pakistan.

As a rookie agent, Maya is brought in to watch the questioning of a suspected al-Qaida operative. The interrogation soon turns to torture (much of which is implied), and Maya is repulsed. The agent in charge, Dan (an imposing Jason Clarke), tells the suspect he’ll eventually give up the information the CIA wants.

“In the end, everybody breaks, bro’,” he tells the captive. “It’s biology.”

Countless dead ends form a callus on Maya’s soul. Her naivete grows into something fierce and determined. When colleagues are killed in a car bombing, she has her moment of revelation.

“I’m going to smoke everyone involved in this operation,” she vows. “And then I’m going to kill bin Laden.”

Director Kathryn Bigelow and her “Hurt Locker” screenwriter, Mark Boal, deftly quilt together disparate events in the almost 10 years between 9/11 and bin Laden’s death.

They also raise important and complex ethical questions about torture, deceit, politics and war. How lofty ideals actually affect the people on the front lines. It’s sickening to watch a prisoner physically abused and sexually humiliated, but when torture is raised as a political talking point on a TV at a CIA base, you can’t help but feel the agents’ unspoken frustration.

The real strength of this early Oscar favorite, though, is the raid on bin Laden’s compound. The film’s first half feels overloaded with extraneous details. Maya sorts her way through boxes of files, views hours of video footage and spends an inordinate number of scenes looking at a computer screen.

But there’s a method to Bigelow and Boal’s storytelling. The subsequent raid is re-created almost minute by minute.

Under the cover of darkness, the Navy SEAL team goes room to room, not knowing if the next door hides a gunman or a child. The SEALs are supremely efficient. Each shot they fire explodes in the silence. And there’s no doubt they hit their targets.

Bigelow makes us feel some empathy for bin Laden, mostly by using the kids in the compound as weapons against our preconceptions. These children — caught between warring factions — watch helplessly as the adults in their lives are killed by an invading force.

She also creates the ultimate anticlimax. The target meets his fate with nearly zero fanfare.

Despite partisan bluster by a lot of people who probably haven’t seen the film, no one side of the politicized hunt for bin Laden emerges victorious. The administrations of George W. Bush and Barack Obama are little more than unseen corporate bosses levying unattainable mandates.

Nonetheless, it’s important to remember “Zero Dark Thirty” is fiction. Bigelow, Boal and Chastain say Maya was based on a real operative, but Santa Claus once was based on a real guy, too. She’s an amalgam. Viewed as history, the story feels almost as curious as the initial tales of Jessica Lynch, the American soldier rescued by U.S. forces during the second Iraq war.

For the purpose of this film, though, Maya is flesh and blood. That’s a credit to Chastain.

She grows from a soft and brilliant rookie to a hard-hearted holy warrior. After several near misses and outright assassination attempts, she tells a colleague, “I believe I was spared so I could finish the job.”

There are several other strong performances: Kyle Chandler (“Friday Night Lights”) straddles the line between taskmaster and put-upon middle manager. James Gandolfini has such a presence as an unnamed CIA director that when Maya confronts him, it seems like career suicide. And Chris Pratt transforms his big puppy shtick from “Parks and Recreation” into the eagerness of a Navy SEAL. Many more familiar faces pop up. The film’s cameo count rivals that of “Lincoln.”

“Zero Dark Thirty” occasionally feels like federal propaganda with art-house sensibilities and Oscar aspirations. But while the story of “Zero Dark Thirty” might not exactly be journalism, it brings home this truth: The success of the bin Laden mission — like many other battles in the war on terror — depended on many people whose names we’ll never know.

THAT TITLE

Zero Dark Thirty refers to the time Navy SEALS set foot on the compound where Osama bin Laden was found and killed. “Zero dark” is midnight; “thirty” is 30 minutes after midnight: 12:30 a.m.

What others are saying

• Christy LeMire, The Associated Press: “Jessica Chastain’s powerfully controlled performance — a spectacular showcase for this versatile actress’s many talents and a long-overdue leading role — is emblematic of the film as a whole.”

• Manohla Dargis, The New York Times: “A cool, outwardly nonpartisan intelligence procedural — a detective story of sorts — in which a mass murderer is tracked down by people who spend a lot of time staring into computer screens and occasionally working in the field.”

• Roger Moore, McClatchy-Tribune: “The film is a fascinating reconstruction of history. But it’s surprisingly unmoving, a clinical exercise that mimics the professionalism of those involved.”