One night in July, 2010, Shannon Sedgwick Davis, a lawyer and activist from San Antonio, Texas, and the mother of two young boys, found herself seated across from the chief of the Ugandan Army, General Aronda Nyakairima, at his hilltop headquarters, in Kampala. “It was one of those out-of-body experiences,” Davis told me. Davis was on the verge of becoming deeply involved in the campaign to capture Joseph Kony. In the course of a quarter century, Kony abducted tens of thousands of people, mostly children, and conscripted them into the Lord’s Resistance Army (L.R.A.), which was conceived as a Ugandan rebel force but whose primary target has been civilians in several African nations. “I am a full-blown mom, sitting here with this Ugandan general,” Davis said. “And I can’t believe I have an audience with this man, and that he didn’t write me off as crazy.”

Davis had two questions for Aronda: Would military trainers and communications make it easier for the Ugandan Army to chase down Kony—who is wanted by the International Criminal Court—in the jungles of Congo, the Central African Republic, and Sudan, where he and his commanders have scattered, and, more important to her, rescue the women and children still in his clutches?

Yes and yes, said the general. His eyes looked so tired, Davis recalled, that she hadn’t been sure she had his attention. “You almost want to pry them open so you make sure he’s still listening. But he said they would welcome any assistance, and that it was their problem to solve.” It was late, and in that first meeting Aronda seemed unsure what to make of this passionate, small blond woman from Texas. But the meetings persisted. Together, they began to map out what the general wanted and the guarantees that Davis would require from the Ugandans before embarking on an unorthodox venture: the charitable organization she heads, the Bridgeway Foundation, would hire private military contractors to train an African army.

“I looked at him and said, ‘I know this is highly unusual. We’ve never done anything like this before,’ ” Davis told me. “If you asked me to script my life with the most crazy possibility, I could not have scripted this. So I need to go back to the U.S. and find someone smarter than me to advise me on this. I’m sure he was thinking, That is the last time I’ll see her.”

The operations that Davis would help set in motion—which have remained under wraps for more than two years—have helped to transform the Ugandans’ pursuit of Kony. He has been driven from his safe haven, in Sudan, and the Ugandan troops, aided by African Union forces and American advisers, are now close on his trail.

Davis has played a unique role in the long war against Kony since 2006, when she first began to help fund advocacy groups and activists working on the issue. “She is so down to earth,” said one high-ranking Ugandan officer, who has spent a lot of time with her. “She never throws her weight around like most Americans.” Advocacy groups and human-rights analysts working in Africa’s Great Lakes region have great respect for her work. Government officials are more wary. Not because they don’t like her or what she’s up to—I’ve never met anyone who didn’t—but because they don’t know how to process it all. “It all sounded so ‘Charlie Wilson’s War,’ ” one U.S. official said—a reference to Joanne Herring, the wealthy Houston activist and talk-show host who teamed up with the Texas politician to train and arm mujahideen fighters to take on the Soviet Union in Afghanistan. (Julia Roberts played her in the movie.) Davis couldn’t be less like Herring. She’s no socialite, and she has avoided any press out of a conviction that this was the Ugandans’ fight, and that her role would be misinterpreted.

Davis presents herself as all mom and all passion, driven by a progressive Christian faith. She is also the C.E.O. of the Bridgeway Foundation, the charitable arm of Bridgeway Capital Management, an investment firm with more than two billion dollars under management that gives half its after-tax profits to organizations working to end genocide and protect human rights. (Davis is also a Bridgeway shareholder.) She sits on the advisory council of The Elders, the supergroup of global statesmen that includes Nelson Mandela, Desmond Tutu, Kofi Annan, and Jimmy Carter. Earlier in her career, she worked with the International Justice Mission and forced her way into the Cambodian brothels of Svay Pak, to liberate young girls sold into the sex trade. She is impatient with half measures.

When I met Davis, this past summer, she was living in Rwanda with her husband and two children and their pet chicken. Bridgeway has funded projects there to assist widows and orphans, and has collaborated on the country’s genocide archive. Davis is deliberately understated: in Rwanda, she drove herself around; when we met, she wore a striped pullover with jeans and short boots. She wants her children to have a sense of her work, so she keeps a journal for them, which she updates every night. Around her neck hangs a charm of St. Jude, the patron saint of impossible causes; Bridgeway’s founder, John Montgomery, carries one as well.

Davis told me when we spoke again in New York this past week, that, in 2010, she realized that she had to move beyond advocacy. Ida Sawyer, Human Rights Watch’s lead researcher in Congo, whose work Bridgeway was helping to fund, had uncovered evidence of previously unknown L.R.A. massacres that had taken place in December, 2009. “She told me, ‘Shannon, I have some bad news,’ ” Davis said. Sawyer had travelled with a Congolese activist from village to village, along the so-called Trail of Death—a sixty-five-mile swath of destruction, along which the L.R.A. had murdered three hundred and twenty-one civilians and abducted two hundred and fifty people, including eighty children. Sawyer told her that Kony’s rebels—child soldiers among them—had tied victims to trees and hacked them to death with machetes and axes; women and children were not spared. “The massacres happened near a U.N. base, and the U.N. didn’t respond,” Davis said. “We not only didn’t do anything to stop it but all these people dropped off the face of the earth, and no one knew about it until brave Ida goes up there on a motorbike.” She was choked up as she talked. “That’s when I realized we had to do more.”