There must be something said for a woman under the age of 30 who can walk into a room full of the industry's most powerful (and most cutthroat) executivies and command the respect many who are twice her age and have been working longer than her life can only dream of. It's almost unimaginable. Even harder to believe is that a woman who has been a full-time player in Hollywood for less than a year is not only going to stick to her guns when facing Harvey Weinstein's wrath, but forcefully tell him to “f--- off” and somehow, somehow not find herself immediately blacklisted straight to Hell. That woman is Lo Calley, the 26-year-old daughter of self-made billionaire Ivan Milenković, and you can thank her for the most important film of the year: Zero Dark Thirty.

When the Oscar-winning team of director Kathryn Bigelow and screenwriter Mark Boal decided their follow-up to The Hurt Locker would focus on the killing of Osama bin Laden, both knew they would have to go far off of the beaten path to find financing that didn't come with a political agenda and a bloated ego that would distort their vision. They shopped their project around to at least half a dozen independent financiers, hoping to find the money through a piecemeal approach, but Calley sat the formidable couple down on the balcony of her Hollywood Hills home and told them in no uncertain terms that she would finance the entire production with no strings attached. And then she did. To the tune of 45 million dollars. “Laurie reminds me a little of John Grady Cole,” says director Andrew Dominik, referring to the 16-year-old cowboy who rides into Mexico in Cormac McCarthy’s All the Pretty Horses. “She is not going to argue with you, but she’s going to get what she wants.”

Now, just a year later, the unassuming Calley is the talk of the town and cinephiles stay on the edges of their seats awaiting news of what her, and her company's, next move will be. Tall and attainably pretty, she looks more like a starlet whose bread and butter are romcoms where she plays a cute hipster MPDG than a power player who gets hard-hitting films made with just her wallet and charm. She drives a '68 Corvette, is unafraid of not being taken seriously when she shows up for meetings in flowery sundresses, and carts a rolling bar around the OMP offices like she's Roger Sterling. Soft-spoken but not shy, she has a built a reputation of being a warrior for her filmmakers and a friend to the stars who fill out the casts.

One of many allies she has made in the business, Charles Roven of Atlas Entertainment, notes how easy it would be for Calley to “dial it in, send the money, go to the premieres” but she can often be found on or near the set of the projects she has taken under her wing. More surprisingly, she seems to be regarded as a welcome presence. She keeps her meddling to a minimum and, according to reports, generally acts as a hybrid cheerleader/therapist for the cast and crew. During the nearly four month shoot for Zero Dark Thirty, Calley made appearances at filming locations that included England, India, and Jordan.

With the controversial subject matter and the project's high profile, filming was strained at times by butting heads and wavering moods, but Calley became close with many of those involved with the movie. Especially Alexandra Cassel. (“Lo is just crazy about Sasha,” says someone who runs in their circle.) In the years to come, the story of how Cassel became the star of Zero Dark Thirty will likely become a prized trivia subject for film buffs. After being dismissed by Cassel's agent without even an opportunity to speak with the actress, Calley hunted down her eventual leading lady's personal cell phone number and called her up. When she found herself with no answer and no follow-up, she sent a text: “If I ever ask you for anything in my life, it’s to call me back for five minutes.”

“I said, ‘That’s very dramatic, what is it you need, missy,’ ” says Cassel. “And Megan said, ‘Well, we have this film, and Kathryn Bigelow wants you. Your agent won't pencil me in and I don't have the patience for middle men. I swear on my life, I'll move the sun and the stars if you let us fly out to wherever you are and show you this script.’” Cassel laughs. “Lo was so determined and passionate. This girl then really went to town [negotiating the deal] to make sure I got on the picture.” The reward for Calley's persistance in seeing Bigelow and Boal all the way through? Oscar nominations practically around the board, including a Best Actress nod for Cassel.

Despite a grueling filming schedule, the film's stars were more than happy to stick around the producer even when the cameras had stopped rolling for the day. Cassel and Calley often spent evenings holed up and watching television they'd missed. “We’d order food, pig out, watch Game of Thrones together, and relax,” the actress recalls. Ellison also befriended Jason Clarke, the Australian who plays the film’s male lead, a spy experienced at torturing suspected terrorists for information. “Megan was so generous, always keeping our spirits up with a good bottle of wine,” he says. He and Ellison rode motorcycles through Chandigarh, India, and took a trip to the Taj Mahal together. “Some nights, Megan would knock on my hotel door and say, ‘I can’t sleep, can you?’ ” recalls Clarke. “We’d go up on the rooftop of the Marriott hotel for some gin-and-tonics, looking out over the city. She had the same wonderful naïveté that I had that we were in this incredible place making this incredible movie. ‘Man, this is it! This is what we’ve always wanted to do in life.’ ”