We enter the lobby of a small Beijing hotel unnoticed and walk quietly to the second floor. My companion, an ethnic Korean missionary from a western country, glances around the hallway before tapping on a door. Someone peers through the peephole before cautiously opening the door.
The woman is nervous when she sees a foreigner enter the room, but then relaxes. Park Sun-young (not her real name) is used to fear. For the past five years, the 36-year-old North Korean has evaded police, women traffickers and North Korean agents who prey on refugees in northeast China.
If all goes well, her life of hiding will end within 24 hours, if the missionary succeeds in getting her into a foreign embassy or consulate with the help of the intricate 'underground railroad' that is helping refugees escape China.
Such defections have become more difficult. As many as 400,000 North Korean are estimated to have fled their food-starved Stalinist state and poured into China in recent years. They made the front pages around the world in 2002 when some began throwing themselves over the walls of foreign embassies and consulates in the Chinese capital. Those who succeeded were quietly sent to third countries to avoid embarrassing China, North Korea's closest ally. Most ended up in South Korea.
The central government responded by stretching extra rolls of wire around foreign embassies and consulates and by beefing up the numbers of police. This, in turn, forced the underground railroad to become more creative.
These groups now focus on remote border areas, where refugees can flee China with fake passports. 'Once they cross the border, it's still not over,' says a source in Beijing. 'The Thai, Laotian, and Burmese police are after them, and some of these countries have good relations with China and North Korea.'
Fortunately for the refugees, there are church workers and foreign intelligence agents also waiting for them, says a diplomat in Beijing. If they get to the refugees first, they are usually taken to a South Korean embassy or consulate, and then to Seoul. About 40 North Korean refugees were detained in Laos last year, but escaped to Thailand with the help of non-government organisations (NGOs) and Christian groups, the South Korean media reported last year.
About 850 North Koreans are reportedly being held in four detention centres in northeast China awaiting deportation. Those repatriated face brutal treatment. Human rights investigator David Hawk last year wrote a report called The Hidden Gulag: Exposing North Korea's Prison Camps. Based on interviews with former prisoners and escapees, he says North Koreans forcibly repatriated from China were thrown into an 'extremely brutal system of imprisonment, interrogation, torture and forced labour'.
Hawk says the prison system in North Korea is 'characterised by very large numbers of deaths' as a result of forced labour and 'deliberate starvation-level food rations'. He also describes 'guilt-by-association imprisonment for up to three generations of supposed wrongdoers' families'.
Some of the westerners and Koreans most active in helping refugees are fiercely anti-communist and have close ties with conservative groups in the US. According to one foreign diplomat in Beijing, elements in the Bush administration are keen to encourage mass defections from the North in an attempt to destabilise the Pyongyang government. 'Even if this means there's instability in China, that's OK,' says the Beijing source. 'The purpose is to make the North Korean government collapse.'
As we sit and talk in her dimly lit hotel room, Ms Park tells her story. She says she never intended to leave North Korea indefinitely, explaining that her brother had a good job, and that she, as a youth propaganda worker, had a better life than many of her compatriots. 'We were middle class; we didn't know hunger,' she says. She left her husband and nine-year-old daughter behind, enticed by a friend who had returned with stories of riches across the border.
'My friend told me that a lot of North Koreans go to China and make money. She said, 'Let's just go for a week and then come back'.' Things went wrong when Ms Park took off her jacket and handed it to one of her companions - a simple act that was to change her life.
A North Korean soldier following them to the border caught one of her two companions just before they entered the Tumen River. 'The slowest one was caught.' she says. The woman had her jacket with her ID card inside. North Korean security knew who she was, and her fate was sealed.
A frightened Ms Park quickly waded across the waist-deep water, too afraid to look back. 'The guard ran to the border screaming at me, telling me to come back,' she says, tears welling in her eyes.
Like many North Korean refugees, Ms Park has received help from China's underground church network, and has become a Christian. She was able to buy a counterfeit ID with US$1,000 given to her by a church, and the missionary found money to treat her tuberculosis.
She says that, as a converted Christian, she is in greater danger if she is returned home. 'One of the first questions they ask is 'Did you become a Christian?'' she says. 'They punish you harder if they think you're a Christian.'
Nam Sin-u, a South Korean architect working in New Jersey, who has been active in helping North Korean refugees, confirms this. 'If a refugee ran away simply in search of food, or if he or she is a child, they will be let go with a light sentence,' says Mr Nam. 'But if the refugee tried to defect or converted to Christianity, the punishment when repatriated is very harsh.'
Ms Park says she was lucky after arriving in China. Afraid of getting caught near the border, she spent four months in Heilongjiang province. She then went to see the friend who crossed the border with her, who has since married a Chinese Korean. Ms Park moved in with the family. But afraid of being arrested, she seldom left the house. Ms Park says that, as a propaganda worker, she once sneered at religion. 'When I first came, people urged me to go to church, but in North Korea there's a lot of propaganda portraying religion as negative and ridiculous,' she says. 'I thought it was unbelievable that people believed in God.'
But this changed. 'I started to believe in Jesus and since then life has been wonderful. I was always afraid of being caught, but when things got really bad, I prayed.'
Her deep commitment to the Christian faith is another reason why she was singled out for assistance and perhaps demonstrates that church denominations have more riding on the underground railway than simply compassion for suffering refugees.
'There's a long line of people waiting to leave, but she was more feasible,' says the missionary. 'We think she'll be a very strong church leader in North Korea in the future. She'll head back when the door opens. We see a lot of potential in her.'
The New York Times commentator Nicholas Kristoff recently argued that the situation of refugees was paradoxically being made worse by some of the people trying the hardest to help them, and he pointed to Evangelicals and conservatives. Kristoff says that the underground railroad embarrassed Chinese leaders into forcing refugees - 'some of the sorriest and most helpless people you can imagine' - back at a rate of 100 a week.
'So dozens of North Koreans were helped, and tens of thousands were harmed,' he wrote.
Mr Nam says Kristoff should know better. 'The refugees are not living like human beings,' he says. 'They're living like animals and slaves. It's only because the NGOs made trouble and reporters wrote about these incidents that we know what's going on.'
All signs point to a growing influx of refugees. The World Food Programme (WFP) says that, despite improvements since the late 1990s, malnutrition rates in North Korea 'remain disturbingly high'. The WFP said the government-run Public Distribution System planned to provide just 300 grams per person per day to urban residents this year, less than half of a survival ration. The UN body said recently that, due to falling foreign donations, it would have to significantly reduce food aid to 3.8 million North Koreans next month.
South Korea's Reunification Ministry said in December that 1,140 defectors had reached the South last year, almost double the number for the previous year, and 10 times the figure for 1999.
Mr Nam, a fierce critic of the Pyongyang regime, says 1,400 North Koreans are dying each day due to poor government and resulting food shortages. 'The more refugees at the consulates, the better,' he says. 'Let them come; let them all come.'
Park Sun-young is fortunate. A call comes on my mobile early in the morning two days after our meeting. 'Our friend has arrived safely,' the caller says, before hanging up.