Zero Dark Thirty is Homeland without bipolar disease and sex scenes… just an inside glimpse at hardcore CIA work to find Osama bin Laden.

Although star Jessica Chastain only appears sporadically in the previews, she basically IS the movie. She plays a CIA agent named Maya, who almost singlehandedly locates mastermind terrorist Osama bin Laden over the course of several years by systematically following her research.

The film starts just as 9/11 happens, with disturbing images and real-life emergency calls from people inside the Twin Towers, reminding us again of the horror of that day. It certainly sets the tone. Then we jump ahead a few years and meet Maya, an eager new recruit sent to Pakistan to assist on the interrogation/torture of suspected terrorists. Slowly, we see how she is toughened by her surroundings, as she soon develops a credible theory that if they find the man known as “Abu Ahmed,” who is the personal messenger of bin Laden, they will find the terrorist himself. It’s sort of like the All the President’s Men phrase “Follow the money”; follow Abu Ahmed and you’ll find Osama.

Maya is met with much opposition — from her colleagues, from several wrong turns and disinformation — but she doesn’t give up and when she finally finds the right thread, after so many long years, her hard work pays off. Zero Dark Thirty is a long journey (nearly three hours), but the last 30 minutes or so sufficiently sum up the intensity as the Navy SEALs go into bin Laden’s compound and do what we now know they all did.

It’s Chastain’s performance that dominates the film, earning her the distinguished frontrunner position for Best Actress in the Oscar race. She plays Maya with an equal amount of smarts, determination and, at times, vulnerability. She clearly has “Oscar” moments, including a scene in which she chews out her boss (played by Kyle Chandler) or the scene when she simply informs a room of male mucky mucks she is the “motherf***er” who found bin Laden’s compound. But it’s the final scene of the film that could hand her the Oscar, in which the whole weight of Zero Dark Thirty shows on her face. If Chastain loses, it’ll be a surprise, but you can bet she won’t be Oscar-free for long; she’s in it for the long haul.

Granted, the actress is surrounded by a bevy of great actors, including James Gandolfini, Mark Strong and especially character actor Jason Clarke (Lawless), a CIA agent who specializes in torture interrogation. But the other big star of Zero Dark Thirty is director Kathryn Bigelow, who continues to prove she, too, is in it for the long haul. As the only female director to win an Oscar for the intense The Hurt Locker, Bigelow had only her own big war shoes to fill and taking on such a controversial subject had to be daunting at times. There has been much speculation and criticism on how she and the producers obtained the information about the super-secret CIA mission or how accurate it is, but the end result is the same and that is what counts. In Bigelow’s hands, Zero Dark Thirty is thorough, almost too methodical at times, riveting and visually alerting. It may not produce the same gut punch reaction that Hurt Locker did, but it comes close. I’d love to see Kathryn tackle a Civil War movie next.