Second in a four-part special report

At 1 a.m., the bell rang. You Mi Kim rushed with eight other Korean masseuses to the barren front lobby of Sun Spa in San Francisco. The women lined up on an L-shaped couch in their lingerie and waited for the customer to choose.

[Podcast: Meredith May with a South Korean woman who counsels sex trafficking victims. ]

"Don't pick me, don't pick me," You Mi thought, forcing a smile.

Less than a year earlier, she'd been a college student in South Korea, only to be tricked into leaving her home by sex traffickers offering promises of a high-paying hostess job. Desperate for a way out of her $40,000 debt, You Mi bit. Now, she was at the end of yet another 15-hour shift of forced sex.

The man examined You Mi's petite frame, her brown eyes and her dark hair, which fell like silk to her shoulders.

He pointed at her.

You Mi led him from the lobby to one of the four upstairs massage rooms and told him to shower in the bathtub behind a curtain in the corner.

"This is my first time," he said.

It was a line You Mi heard daily inside Sun Spa.

The man was athletic, muscular. After showering, he led her to the bed and stretched out on his stomach. You Mi began massaging his shoulders.

Suddenly, he jumped off the bed, declared he didn't need a massage and yanked off her white camisole.

He threw her to the mattress and forced himself on her, pulling her hair and twisting her small body in so many ways that she screamed in pain.

Then the man's eyes went blank. He began choking her. She heard sounds of pleasure escape his throat. He seemed to be enjoying it.

The manager burst through the door. "What's going on?" she shouted in Korean.

"Help me!" You Mi gasped.

The man released his grip. The manager turned her attention to the customer.

"I'm sorry she disappointed you," she said, refunding his $50. A disgruntled john might tip off the police.

The man pocketed the money, turned and walked out the front door.

Of all the degradations You Mi endured while forced to work as a California sex slave in 2003, this was the worst. In an instant it became clear: Her life amounted to $50. The manager ordered her back to work.

After her attack, You Mi did the only thing she could think of to survive. She wiped away the tears and smiled for her next customer.

For nearly a year, You Mi was caught in a sex-trafficking triangle -- starting in South Korea, one of the world's leading importers and exporters of sex slaves, and stretching to the exploding Asian outcall market of Los Angeles and then to the Asian massage-parlor mecca on the West Coast: San Francisco.

She would be forced to have sex with dozens of men a week in seedy massage parlors, apartments and hotel rooms. She would live under the watchful eye of guards and surveillance cameras, reminded constantly that her family back in South Korea would be harmed if she ran.

She would work in brothels with blacked-out windows and double metal security doors, allowed outside only under the escort of crooked taxi drivers working for the traffickers who drove her to sex appointments. She would also be trapped culturally, unable to speak more than a few basic sentences in English, unaware of where she was and dependent on her captors for food and shelter.

To traffickers, 22-year-old You Mi was the perfect victim: a small-town girl in financial trouble. She gave her trust, and in return her life went horribly wrong, terribly fast.

This is You Mi's hometown, also known as the San Francisco of South Korea. Situated on the southeastern tip of the country, Busan also has steep streets, summer beach tourists and even a white version of the Golden Gate Bridge.

Busan is also the birthplace of South Korea's sex industry, where Japanese troops built the first brothels after invading the country in 1904.

But the selling of Korean women goes back to the 15th century, when wealthy men bought educated Kisaeng girls to live in their homes and entertain them with song, dance, cooking and sometimes sex.

Today, sex work accounts for 4 percent of the country's gross domestic product, according to government reports. Prostitution brings $21 billion a year -- more than electricity and gas combined. There are an estimated 330,000 sex workers, 80,000 brothels and 69 red-light districts in a country the size of Indiana.

Busan is infamous for Wan Wol Dong, a maze of dark alleys where women are on display in row upon row of "glass houses." A peculiar Korean invention, a glass house is about the size of a parking space, with glass walls on three sides and a mirrored back wall concealing a private bedroom. Women sit on chairs or chaises or on the floor inside, illuminated by red lights that cast a pink glow.

For about $75, men strolling or driving by have their pick of older women in silk bathrobes, younger women in hot pants and even preteens in ballerina skirts and heart-shaped bodices.

Glass houses are just one item on South Korea's sexual menu. Sex is sold out of bars, restaurants, coffee shops, barbershops, tearooms, karaoke bars, saunas, massage parlors, over the Internet, in skin-care shops and hair salons, in computer rooms called PC bangs, in "love motels" and in nightclubs near U.S. military bases.

Even something as simple as ordering coffee has been sexualized. "Ticket tabang" girls make home deliveries with thermoses of coffee to sex-seeking callers.

While a 2004 South Korean law targeting pimps and buyers has slowed foot traffic in the open-air sex markets, early signs indicate that the crackdown has had the unintended effect of fueling international sex trafficking. Pimps simply go online or overseas -- mainly to Australia and the United States -- where demand is high and risk is low. They recruit in cities like Seoul and Busan, where most of the country's universities are located.

When You Mi was a little girl, her family -- like many others -- partly supported itself on the sex trade. For one year, her mother managed a room salon, where women in skirt suits pour drinks, sing karaoke, dance and, if asked, retreat to a private room to have sex with customers. Considered playpens for the wealthy, room salons attract businessmen who spend the equivalent of $1,000 for a few hours at a table, and seal their corporate deals with sexual entertainment instead of handshakes.

The room salon was off-limits to You Mi and her younger sister, although sometimes her mother would ask her to fetch dried squid and other snacks for the family business.

Mostly You Mi spent her days at elementary school and her afternoons perfecting her skill at a Korean version of double-Dutch jump rope. She spent so much time jumping over two elastic ropes stretched by two of her girlfriends that she developed large calf muscles and the nickname "Drumstick."

She dreamed of becoming a policewoman.

You Mi's family lived in one of the poorer neighborhoods of Busan. The family budget got even smaller when her mother's room salon went out of business, and all they had was her father's carpentry income. Her mother tried opening a restaurant, selling boiled eggs and sticky rice as a street vendor, and running a karaoke bar, but those ventures also failed. You Mi and her sister knew never to ask their parents for spending money because there never was any to spare.

Money was tight for all the families in her neighborhood, so You Mi never felt deprived. But in 2001, when her family had to struggle to come up with nearly $6,000 to send her to a university closer to the city, she realized her family was poor. At college for the first time, she was surrounded by friends who came from the glittering beach high-rises.

They knew things, like how to wear makeup, which bars poured the strongest soju -- the Korean version of vodka -- and which hairdressers had the longest waiting lists.

And they had something You Mi had never seen before -- credit cards.

A friend explained to You Mi that she could buy things without cash. A magic card, You Mi thought.

She had to have one. After school, You Mi took the bus to Seomyeon, a shopping district jammed with neon-covered multistory department stores and an enormous underground mall beneath eight lanes of traffic.

A street vendor was eager to sign her up for a Samsung credit card. She filled out the application truthfully, except for the part about her home address. She knew her mother would not approve, so You Mi put down her friend's address instead.

The vendor didn't explain debt accrual and interest rates to You Mi.

As she waited for her card to arrive, she began to fantasize about a future with buying power. She dreamed of changing from a caterpillar to a butterfly -- from an awkward girl in a school uniform to a glamorous sophisticate wrapped in fashionable clothes, jewelry and perfume.

Getting a credit card would make her a woman.

She and five friends from school descended a staircase from the sidewalk down to the mall. Hundreds of girls walking arm in arm crowded the halls, laughing, shopping and talking on cell phones. Store upon store, no larger than walk-in closets, offered a paradise targeted at You Mi's generation: metallic handbags, low-rise jeans, high-heeled boots, skin-care creams, digital cameras and American-style sneakers.

You Mi wasted no time. She bought a handbag, shoes and a new jacket. She went to a wall of ATM machines and pulled out a couple of hundred more so she could get her hair done at a salon.

She felt grown up. She felt popular. When she invited her group of friends to dinner and drinks at a soju bar, they all said yes.

By the day's end, she had spent the equivalent of $600. She felt a pang of worry about how she would pay the money back without a job. But a week later, the pang had subsided. It was Friday, and her friends wanted to go out again.

Soon, the Friday outings became a regular habit for You Mi and her companions. Her wealthy friends rarely offered to pay after the pork cutlets and kimchi were eaten, but You Mi relished her newfound generosity and didn't complain.

It was easy for her to get sucked into the shopping culture in Busan. Fashion is a major cultural preoccupation for South Koreans, who crowd the glittering neon shopping districts at night to window-shop and people-watch. Designer labels create the dividing lines among social classes, and women dress in fur, cashmere and heels just to run errands. Street beggars are nonexistent, and poverty is considered a mortal sin.

Such intense pressure to acquire "American luxury goods" puts the average South Korean family in $30,000 credit card debt.

Once You Mi started wearing nicer clothes, she noticed people were more willing to be her friend.

She bought so much that she had to sneak her purchases into her room at night. When her mother questioned some of the new clothes, You Mi explained that her new college friends were letting her borrow them.

She could keep her mother at bay, but not the Samsung credit card division. In South Korea, cardholders can be taken to court if they are 90 days late on a payment. It's not uncommon for credit card companies to enter homes and red-tag the possessions, even repossess the home itself.

After a year, in 2002, You Mi owed $10,000. Samsung cut her off. So You Mi called one of the dozens of moneylenders advertising quick cash in the free weekly newspapers, and he gave her $2,000 at 25 percent interest, plus $140 monthly fees.

You Mi was stuck. She quit school to get a job selling tokens and drinks in Lucky 7, a gambling hall, so she could start making payments on the card.

You Mi told her parents she was taking a year off to raise money for tuition. Her younger sister was starting college that year, and her parents couldn't afford to send both girls. They were proud of their eldest daughter for being so responsible.

Although You Mi earned $650 a month during her year at Lucky 7, she was still spending. She turned to moneylenders five more times to get increments of $2,000 to finance shopping trips and nightclub outings with her friends. She knew her behavior was reckless, but she was addicted to money's power -- the attention it drew from friends and the feeling of generosity it gave her.

With each passing day, she worried that Samsung would take her family's house.

Then You Mi took out a second credit card to pay off all the loans.

She was too ashamed to tell her friends or family about her mounting debt. She wanted to fix it herself without burdening anyone. Two years after getting the original credit card, her combined debt hit $40,000.

Before her were hundreds of ads for sex workers: escorts, room salon girls, masseuses, exotic dancers and outcall services. Some offered jobs in America, Japan and Australia as "waitresses and models."

A year at the gambling hall had done little to erase her debt. High-paying jobs are limited for Korean women, and nearly nonexistent for young women without a college degree, like You Mi. The idea that college is a place for women to meet eligible husbands is still widely held in a country where it's rare to see a female politician, judge or professor.

It's common knowledge that the sex trade employs many women in Korea, yet people rarely speak of it. By middle school, some girls are already financing their wardrobes by selling themselves over the Internet.

So by fall 2002, You Mi began to wonder whether she was willing to do the unthinkable: sell her body.

Like most girls in South Korea, You Mi knew not to answer the ads for "coffee delivery girls" who work in ticket tabangs, the dreariest and lowest-paying job in the sex industry. The ticket tabang, the poor-man's sex outlet in rural farmland areas, attracts teenage girls who are just starting in the sex business, and who can be bought for as little as $20 an hour.

She also didn't want to be a "juicy girl," forced to live and work in one of the many nightclubs that cater to the 36,000 American soldiers in South Korea. If the juicy girls don't persuade soldiers to buy them enough $20 drinks in a night, the club owner requires them to have sex with customers -- the equivalent of five drinks.

You Mi looked over the ads for room salons. She knew that the first round inside a room salon, pouring drinks, is never enough. Women always have to go to the second round -- having sex -- if the customer asks for it. And the customer always does.

The longer You Mi searched, the more it became clear to her that she couldn't stomach the thought of having sex with strangers for money.

After looking for a week, You Mi found on the Internet what appeared to be the perfect solution.

"Work in an American room salon. Make $10,000 a month. Very gentle. No touching. No second round."

She was dubious. She had never heard of a sex-free room salon before, but maybe in the United States things were different.

You Mi did the math. She could work for six months, pay off the credit card and moneylenders, and use the remaining $20,000 to fly back to Korea and re-enroll in college, maybe even get her own apartment. Easy.

He was short on details, but told her she would pour drinks for men in room salons in Koreatown in Los Angeles.

"Is it gentle, no touching with customers like the ad says?" she asked.

"Yes, this is an American room salon; it's different than the ones in Korea, there's no sex," he assured her.

You Mi wanted it to be true. She needed it to be true.

She didn't have a visa or a passport. And she certainly didn't have the $7,000 fee the broker told her it would take to get her to Los Angeles through unofficial channels.

"Don't worry about that," he said. "You can pay it back later from your earnings."

You Mi was frightened about leaving home with underground travel brokers. Her mind, though, was consumed with her mounting debt. The next day, she called the broker and said yes.

She told her younger sister she was going to America for work, but to keep it a secret from her parents, who would never grant her permission to work abroad. You Mi told her parents she was going to Seoul to be a golf caddy -- one of the few legal women's jobs that bring hefty tips from rich men.

She planned to tell them the truth after she paid off her debts.

You Mi was instructed to take passport photos and give them to a man named Kevin in Seoul. The broker drove her to the city, and two days later, You Mi had her passport.

A different broker took her to the airport in Incheon, where she joined another Korean woman, a room-salon worker on her third trip to America. The broker handed them tickets to Mexico City.

"You told us we were going to America," protested You Mi, who did not know a stopover was part of the plan.

The broker was exasperated.

"Didn't the broker in Busan explain this to you? Why are you asking me all these questions?"

You Mi felt something wasn't right, but the promise of financial freedom beckoned.

She swallowed her worry and boarded the plane.

The plane stopped in Japan, Los Angeles and finally Mexico City. It was February 2003. You Mi had been up for more than 24 hours, and everything seemed blurry. She had never been on a plane, she had never heard Spanish spoken, and she was starting to doubt her decision to come in the first place.

At the airport, a Korean man was waiting for You Mi and her flying companion. He treated them to a meal, and gave them $500 each. You Mi didn't realize it, but that spending money would be added to the debt she owed her traffickers. Then he went to the ticket counter and asked in Spanish for two tickets to Tijuana.

A second Korean man met the women at the Tijuana airport, drove them to a hotel on the border and checked them into the same room. He took their passports and told them to stay in the motel.

You Mi did as she was told.

Four days later, the second Korean man returned to the motel and handed You Mi a visa with a photo of a woman who looked a lot like herself.

"Memorize her name and information," he ordered.

The man said they were going to be driven through the San Ysidro border checkpoint with the fake documents. Two drivers were ready -- one for You Mi, and one for the other woman.

"It's dangerous," he warned, "so be careful, and don't shake or look nervous because you'll draw suspicion from the customs agents."

He told You Mi to take only a few outfits from her suitcase and carry them in a smaller bag so it would appear that she was returning from a brief Mexican vacation.

You Mi was confused. She turned to her traveling companion and tried again to figure things out.

"Why do we have to cross illegally if we have passports?" she asked, referring to the passport that traffickers in Seoul had created for her.

The woman explained that Koreans need visas to get into the United States, but not into Mexico or Canada. Because it's difficult to obtain legitimate U.S. visas in Korea, it's easier to fly just outside the California border and sneak in.

"You've come this far," the woman said. "Why don't you just cross?"

How we reported the series

San Francisco Chronicle reporter Meredith May and photographer Deanne Fitzmaurice reported this story from South Korea, the U.S.-Mexican border, from Koreatown in Los Angeles and from San Francisco.

The story was told by You Mi Kim to May through a Korean interpreter and is You Mi's version of events. The shadowy nature of the sex-trafficking industry made it difficult to locate traffickers and co-workers who were willing to go on the record to corroborate You Mi's story.

The Chronicle verified the locations of the apartments and brothels where You Mi said she worked. May and Fitzmaurice also went to her hometown in Busan, South Korea, and spent time in her neighborhood, at her university, the casino where she worked and in the shopping malls where she went into credit card debt.

You Mi's attorney shared her knowledge of You Mi's case.

This year, You Mi also recounted her story for the U.S. government, which granted her a special visa for trafficking victims, given only to those who can prove they were enslaved through "force, fraud or coercion." The government's decision was based on interviews with You Mi's attorney, and on You Mi's written story, which was translated into English by the same interpreter who worked with The Chronicle.

You Mi's story was bolstered by May's interviews with more than 100 people over a 10-month period, including female sex-trafficking victims, current and former sex workers, men who pay for sexual services, federal sex-trafficking investigators, owners of sex establishments, U.S. Border Patrol agents, customs agents, U.S. and Korean government officials, university researchers, attorneys and numerous social workers who provide shelter, support and legal aid to trafficking victims.

May's reporting was supplemented by numerous court documents and research papers. She attended sex-trafficking conferences, sat through court hearings and attended a Bay Area police-training seminar on human trafficking. She went inside five alleged San Francisco brothels with Mayor Gavin Newsom and city health-and-safety inspection teams, and witnessed customers, brothel managers and sex workers answering police questions.

May met You Mi Kim in September 2005. Over the course of 10 months, May interviewed You Mi with the help of a professional interpreter provided by Asian Pacific Islander Legal Outreach in San Francisco.

To research the sex culture and trafficking industry in South Korea, May interviewed Bong Hyup Chung, the government's top sex-trafficking official at the South Korean Ministry of Gender Equality and Family. May and Fitzmaurice met women in sex-worker shelters, and visited with more than a dozen agencies that offer sanctuary and social support to trafficked women. In South Korea, May interviewed two women who had been trafficked to California and one to Japan. She spoke with a woman from the former Soviet Union and several from the Philippines who were trafficked into South Korea. She also interviewed six South Korean women who had been forced into the sex trade within South Korea.

May and Fitzmaurice reported from the red-light districts of Seoul and Busan, where women are on display in glass rooms. There, they spoke with Korean military police on patrol, and "fishers," elderly women who beckon customers into the rooms. They interviewed U.S. soldiers in sex clubs near the demilitarized zone, and spoke with the "juicy girls" inside who are hired to entice men to buy them $20 drinks and pay for sex.

May and Fitzmaurice visited businesses that secretly offer sex, including a male-only drinking club called a "room salon," a coffee shop with delivery service called a "ticket tabang," and a "PC bang," an adult-only computer center with private rooms where men have online sex or make arrangements to meet women in person. They spoke with the owners, workers and customers.

At the Korean Institute of Criminology, May tracked down reports depicting the size and scope of the South Korean sex trade and trafficking industry, which were translated with the help of an interpreter. Translators helped May peruse the want ads in Korean newspapers that are used by sex traffickers to lure women.

Like most of the women May interviewed, You Mi was able to recall the exact wording of the newspaper ad that prompted her to seek employment in America. Conversations that You Mi had with traffickers and her traveling companion were based on You Mi's recollections.

In Korea, May interviewed attaches with the U.S. Immigration and Customs Enforcement office, who investigate and help prosecute Korean sex-trafficking rings linked to the United States.

Story by Meredith May And Photographs by Deanne Fitzmaurice Chronicle Staff E-mail Meredith May at mmay@sfchronicle.com.