Kate Roberts stepped out of her aerobics studio into the crackling wind and paralyzing cold of a late winter night in Moscow. Her red leotards, thick gray sweater and sneakers seemed flimsy protection against the snow and subfreezing temperature, but she gambled that she could quickly hail a ride.

As she expected, an approaching Lada slowed and the old man driving the cab pulled over to give her a lift. But the trip didn't last long.

A large black Mercedes soon pulled alongside the Lada, edging closer and closer and finally forcing it off the street. Two men emerged from the Benz. One took a gun and began banging on the driver's side window, Roberts recalls. The old man rolled down the window, a few words were exchanged. He stepped out and returned with a message:

Get out.

She pleaded with him, saying she would be harmed if he abandoned her, but the old man responded, "It's you or me."

"I could be your daughter," she remembers screaming, as one of the gunmen opened the Lada's door, dragged her out and pushed her into the back seat of the Mercedes. Looking pained but remaining silent, the old man drove away.

Inside the black car, Roberts, then 28, recognized her two abductors. Not long before, the same men had strode into Kate's Aerobics, the exercise studio she owned as a sideline to her job as an advertising executive in the post-Communist Moscow of 1995.

The men, members of the Russian mafia, had demanded protection money. But Roberts refused to pay, calculating that they would leave her alone because many of her customers were women who shared beds with mobsters operating in the area.

"I felt I was invincible," says Roberts.

Now the Mercedes was speeding away from the city, into the wooded suburbs. For 45 minutes, the men taunted her, saying she should have paid up, and that now they had to hurt her.

"I thought I was a goner," she recalls. "I was scared out of my brains."

She tried reasoning with them, then promised to pay, then pleaded and shouted. She realized she was not going to talk her way out of this one.

As the car glided through a heavily wooded area at about 30 mph, she opened the unlocked door and jumped, falling on her side and tumbling into the snow. She sprinted away from the road and began darting between trees, sinking into calf-deep snow at every step.

The men drove slowly along the road, trying to keep her in their sights, and shouting at her to return. Eventually, they drove off, either satisfied with simply sending a scare or expecting her to freeze to death.

The experience left her shaken, but clear-headed: "I thought it wise to dissolve the aerobics business," she says.

Years later, she would move to Washington and start another business, a nonprofit called YouthAIDS, dedicated to slowing the spread of AIDS among young people. She would try to save other people's lives, and in the process, redeem her own.

'Supreme Confidence'

It was almost routine in the Roberts house for young Kate to come home from school in the English town of Southport, near Liverpool, and hear her mother, Jean, say, "Well, we're off to -- "

Her father, Peter, was a captain on cruise liners and cargo ships and often took his family along.

Kate spent her 12th birthday on hands and knees, clambering through the narrow passage at the base of the Great Pyramid of Giza. On one trip to the United States, the ship sailed through fog and ice and struck a whale. She once shared a cargo ship with a family of giraffes being ferried in specially made topless containers, their heads bobbing in the breeze, across the Atlantic to Canada.

Roberts finished high school at age 16, then studied hotel and catering management for two years. She worked briefly for Relais & Chateaux, a European hotel group, then landed in the Netherlands, where she learned Dutch and Flemish ("because everybody needs Flemish") and worked finding alternative acts for a theater-restaurant she managed.

Publishing came next. In 1993, following her boyfriend, she wound up in Moscow, where she helped launch the Russian version of Cosmopolitan magazine. "She has always been her own girl, with supreme confidence in herself," Peter Roberts says.

She soon switched to advertising and marketing, working for Bates, Saatchi & Saatchi, where her biggest client was a cigarette maker. When she wasn't flying to remote regions of Russia to cut deals, recalls advertising executive Chris Willingham, "She was always up for a party."

She loved being in Moscow, but the kidnapping changed that. She worried her abductors would find her again.

"I like living life on the edge, but I was getting nervous," she says.

One day in the fall of 1996, she walked to her Moscow office with colleague Linda Hennessey. Men with guns were swarming the building, pulling computers away from the walls, Hennessey says.

Roberts asked the secretary in hesitant Russian what was going on. The secretary nervously replied that if she wanted to see Kate Roberts, Roberts wasn't there, because those men with Kalashnikovs were searching for Kate Roberts, too.

Moving On

The cover of the February-March 1999 issue of In Review, an English-language Romanian business magazine, shows Roberts, dressed in black leather pants, a black turtleneck and black leather gloves, her long hair piled high on her head. Five young female acolytes stare out from the background.

The body language screams: "We're very cool, and we mean business." The headline reads: "Getting Down: Below-the-Line marketers like the '141' agency are whipping the Romanian consumer into shape."

Bucharest is where Roberts landed after the Moscow hullabaloo, physically unscathed but with a new set of nightmares.

The gunmen were revenue agents, sent by the Russian tax authorities who claimed her firm owed millions of dollars in taxes, according to the St. Petersburg (Russia) Times. Saatchi & Saatchi later settled with the Russian government, paying more than $350,000 in back taxes and penalties.

After she and Hennessey left the building, they contacted Saatchi's London headquarters, which "suggested that we should get the first flight out of Russia going anywhere west," Hennessey says.

Roberts flew to England that night.

After a brief stay in London, she moved to Romania as senior account director for Saatchi & Saatchi and managing director for 141, a promotion agency she started under the Saatchi umbrella. She was about to learn, she says, "how to become famous in a small country in a short time."

Mega-events were her forte. She brought all-night rave dance parties to Romania to promote Coca-Cola. She had an affair with a rock star. With her designer clothes and edgy hairstyles, she developed a reputation as the ultimate party-giver. She used all of it in the service of hawking cigarettes, soda, electronics and bubble gum to young people.

Her decision in 1997 to compete for an account developing the country's first national HIV/AIDS prevention campaign was part of the fun. Roberts became "determined to win it," not so much because it was a great public service but, she says, because "I thought it would be cool."

With one of her employees dating the drummer of the top rock band in Romania, Holograf, Roberts arranged an introduction to the lead singer, and promised to help support the band's next tour if he would help her fight AIDS. The deal included writing a song and performing it at the pitch session.

Band members marched into the conference room with their instruments and proceeded to play their song, "I Do What I Want, But I Know What I'm Doing."

"Kate blew us away," says Michael Holscher, managing director for the Romanian arm of Population Services International, a nonprofit that was funding the ad campaign and runs health programs in more than 60 countries.

In short order, she and Holscher produced two award-winning TV commercials, a weekly series on Romania's leading TV network, a documentary on a music television station and a concert for 10,000 young people, Holscher says. They commissioned a corps of peer educators known as the "Love Police," who approached young people during the summer holidays at Black Sea resorts and issued fake "citations" to those not carrying condoms. The Holograf song went on to become Romania's song of the year.

"The result of all this was a dramatic increase in healthy behavior among young Romanians during the first two years of our campaign," Holscher says. "The U.S. Centers for Disease Control documented a 43 percent increase in condom use among young women at first sex nationally."

None of this, he says, would have happened without Roberts, who got access to millions of dollars in free air time.

As Roberts worked on the account, she found herself thinking more about her other work -- peddling candy and cigarettes. Without making a conscious decision, she began working more on the pro bono account than she did for her paying clients.

She still loved the thrill of the limelight, but something was gnawing at her.

A Change of Heart

It was 1999 and Roberts was on a rare vacation, sitting in a tiny mud hut bar "in the middle of nowhere" outside Cape Town. She and her banker boyfriend were touring the country's vineyards, lush countryside and wild animal parks. She had three weeks to relax but found that she couldn't.

"I was very unsettled in the fact that I was doing advertising work," she says. "I felt bad about pushing kids to smoke cigarettes and drink soda pop and eat candy. I had done it for a very long time and I was really soul-searching about the meaning of my life."

Both the beauty and the sorrow of South Africa affected her greatly. She had seen terrible poverty in other places. But in South Africa, there seemed to be "a funeral on every corner."

Roberts stood up from her seat in the hut and walked over to a South African couple. She introduced herself and asked them to describe the biggest problem facing the country.

"It is quite simple," she says they told her. "It is AIDS, and it is killing a third of the continent." Roberts sat down, astonished. She knew from her work in Romania that the disease was affecting Africa, but she had not realized the scope of the problem.

With her boyfriend gaping at her, she began talking, but not to him.

"I suddenly said to myself, 'Are these Gucci shoes what life is all about? . . . I have probably sold a billion sticks of cigarettes and encouraged kids to drink pop and eat all that rubbish that I have promoted. I now see kids in Africa with absolutely nothing but disease and death around them.' "

She began thinking about what motivated her to get up every morning: fashion, travel, music, her work pitching companies for business so that she could earn money to buy more nice things.

"I could not believe I had been this person for such a long time," she says. "I don't want to say I was reborn, because I am not that religious, but something happened and I felt that I needed to refocus my energy and efforts to give back.

"I suddenly realized that I was 30 years old and a third of the way through my life and had nothing to show for it. I wanted to be able to die and say that I had made some sort of difference, even if it was saying that I had saved one life."

At the end of this internal monologue, Roberts looked at her boyfriend and declared, "I'm going to stop AIDS."

She stood up and told him she was leaving South Africa -- and him.

Marketing Life

Country singer Wynonna Judd was reveling in a rare day off in Beverly Hills last February when she got an unwelcome phone call from Roberts.

Roberts wanted to talk about a nonprofit organization she had created called YouthAIDS, to encourage abstinence, delayed first sexual experience, and condom use among young people. Judd's sister, actress Ashley, had already agreed to be a "youth ambassador" for the organization, and all three women had been together at a New York fundraising ball for YouthAIDS in October 2003. Roberts had gone in a loaned Armani dress and Wynonna Judd had stereotyped her as "another alpha female in a ball gown."

Roberts arrived at the hotel that February day and talked for the next four hours "with a missionary zeal" about the tragedy of AIDS and how everybody has a responsibility to help try to stop it. Judd says she laughed, and she listened and she cried, and, in the end: "She blew the doors wide open to my soul. . . . I'd kick anybody's you-know-what with one hand tied behind my back for her."

Roberts was approaching the fight against AIDS by doing what she knew best: selling something by making it trendy.

Her goal is to stop the spread of the disease by changing the behavior of the people most likely to get infected: 15-to-24-year-olds. In today's celebrity-driven world, that requires the use of big names to tell young men to put on a condom, to tell young women to insist on it.

"It's a sad state of affairs when you have to make it [condom use] sexy, bring in Hollywood, but you do," she says.

With Holscher's help, she sold her idea to officials at the Washington-based Population Services International, which provided her money to start YouthAIDS. She moved to Washington in 1999, with a strategy of developing HIV/AIDS funding and awareness as a business, not as a charity seeking a handout.

"We don't just beg for money," she says. "We develop campaigns that are a win-win for both the cause and for the company" that donates money.

She doesn't meet anyone new without talking about her cause, usually in a mini-sermon that comes in one long breath:

"YouthAIDS is a platform for everyone to make a difference. That means individuals, churches, schools, students, corporations, governments, NGOs, rock stars, celebrities and the media. For just $10, the cost of a pizza, you can educate and protect a young person from HIV/AIDS for a year. The problem is ignorance.

"In my experience in the West, no one cares because they think it's a disease for the developing world. The reality is it is on our doorstep and every hour two young people become infected in the U.S. You can essentially save a life and perhaps prevent one of the sex workers in Pattaya [Thailand] from going into the sex trade and allow them to follow their dreams, get an education and become a doctor, experience the joy of love and marriage.

"AIDS is literally the worst pandemic of all time, a sexual holocaust, a threat to all mankind and you die alone. It's not a cause, but an emergency."

She has turned YouthAIDS into a global effort, using theater performances, media, concerts, fashion and sports to reach millions of people. Justin Timberlake, Eve, Destiny's Child and other artists have recorded public service announcements for the group.

She returned to Cape Town, in 2002, this time with musicians P. Diddy and Alicia Keys, doing a global concert with MTV to raise funds for AIDS prevention.

"We took Alicia and Puffy around the townships and had them go to AIDS hospitals and clinics," Roberts says. "When we walked into one of the maternity wards of a hospital for pregnant HIV mothers, they all started singing Alicia's song 'Falling.' It was a big moment, as I know we had changed lives."

"I love her philosophy of using the language of the youth . . . the syntax that is indigenous and popular to one specific area," says Ashley Judd, who in July traveled with Roberts to Southeast Asia for the International AIDS conference. "So you get a star in Nigeria that nobody has ever heard of anywhere else talking to Nigerians about abstinence, birth control and condoms. "

Roberts worked not only on celebrities (Macy Gray and Bono, among them) but also persuaded foundations to ante up, including Melinda and Bill Gates's, which views her "innovative" approach as "very effective in helping young people protect themselves from HIV," says Helene Gayle, who directs the foundation's HIV, TB and reproductive health program.

She persuaded the New York-based Kiehl's company, which manufactures beauty products, to create one for YouthAIDS and donate the profits. Sale of "Eucalyptus" bath and shower liquid body cleanser has raised more than $250,000 since 2002.

She wanted a musical anthem, and met with producer Quincy Jones. He put her together with songwriter Linda Perry, who won a Grammy for Christina Aguilera's hit "Beautiful." For singers, she plans to approach a gaggle of artists who have donated time to YouthAIDS.

Roberts has a staff of six people and a budget of about $2 million a year, she says. But she secures millions of dollars worth of free media time and "guilts" artists into working for free. Flights and other services are donated, too. Hence her nickname "Pro Bono Roberts."

Several people in the corporate and entertainment world say she succeeds because she is relentless, obsessive, business-savvy and insistent that donations are properly spent.

Kevin Carroll, senior manager of worldwide community affairs at Levi Strauss & Co., calls her "the master of Plan B," because when she hits a wall, she goes around it and finds another way to do something.

"She could be a successful entrepreneur, a successful corporate executive, but she chose to operate in the world where people need help," says Charles Goldstuck, president of BMG North America, parent company of the RCA Music Group. "What a talent to be in this fight."

A New Cause

Even if Roberts were content with her life, she has scheduled no time to stop and savor it.

In May, she was a preliminary judge at the Miss Universe pageant in Quito, Ecuador. One evening the next month, she was in New York, attending the premiere of Ashley Judd's movie "De-Lovely," with Bill Rancic, Donald Trump's "Apprentice," as her escort. He introduced her to the show's director, who suggested involving YouthAIDS in the next version of the show, she says.

The next night, she attended both the Special International Emmy and the Cable Positive POP awards, in which VH1 was honored for a HIV/AIDS documentary Roberts helped produce. Her date: Rolling Stone executive Thom Allcock.

The night after that it was dinner with jewelry designer David Yurman, to persuade him to design a pin for YouthAIDS to raise funds.

Then there was a three-week trip to Southeast Asia to attend an international conference on AIDS in Bangkok and visit sites where YouthAIDS programs are in place.

It would be reasonable to assume she has found her life's work. But that old sense of unrest has surfaced again, a wanderlust that will take her not to a new country this time but into a new area of need, a new way to try to save people.

She returned from her latest Asian trip ready to start an initiative targeting teen obesity in the United States. She became interested, she says, because of her own struggle with weight as a young woman, and through Wynonna Judd, who discussed her weight troubles on Oprah Winfrey's television show.

Yes, Roberts says, it may appear that she is changing focus. But she says she is just expanding the fight to another threat to the health of young people.

Already, the beginnings of a stump speech can be heard:

"I was absolutely amazed at the statistics in America. I was blown away by the amount of people I see just walking around the streets with weight issues. It must make them so miserable and, of course, it's very dangerous to your health. They are also discriminated against, just like people with AIDS."

Standing one day recently in the studio of her home in Dupont Circle, Roberts wonders what it would be like to get married and have children. She does want kids, she says, but it's hard to see where they would fit into her life.

In spare moments, she paints in this studio, brush in the right hand, palette in the left. Roberts began painting in Romania. She had just moved from a dark, tiny apartment where she had to tiptoe around roaches to an airy, whitewashed villa, and she felt like expressing her glee. She had never taken lessons, nor has she since. "It just came to me," she says. "Things just come to me."

Kate Roberts, who once promoted soft drinks and cigarettes to youth, has enlisted pop stars to promote safe sex."I felt that I needed to refocus my energy and efforts to give back," Roberts says of her shift from commercial enterprises to humanitarian ones.