Kim, the young and tempestuous North Korean leader, is issuing threats to the outside world, flying missiles over Japan and threatening to strike the United States. For the people of North Korea, his threats are not just bluster. They are a very real part of daily life. Behind the salvoes of missiles, ordinary North Koreans are risking their lives to make this invisible journey out of Kim’s clutches and to safety.

The Thai authorities do not send them back. Instead, they will slap them with a minor immigration violation and alert the South Korean embassy in Bangkok, which will start the process of transferring them to Seoul – not far from where many started their journey.

“I want to learn all about computers,” says a 15-year-old boy who has arrived in Thailand from Laos, just 12 days after escaping from North Korea. “I want to become a computer expert.”

“I want to be good at computers, too,” chimes in his eight-year-old sister, who is playing with an imitation Barbie that a humanitarian worker gave her on arrival in Thailand. It is the first doll she has ever owned, she says.

The brother and sister are two of the 11 North Koreans telling their story to this reporter of their escape after arriving here, on the Thai side of the Mekong River, before turning themselves in to the police. They ask to withhold their names and other identifying information to avoid putting family members still in North Korea at risk of retribution from the Kim regime.

They are recovering from the last leg of a terrifying journey out of North Korea, which started with a dead-of-night escape across the water into China and culminated in a boat ride across a swollen Mekong, which washed them way downstream from where they were supposed to be dropped.

After they had spent hours in the rain, not knowing where they were, the activist who had helped them escape finally found them.

They spend the night in a spartan hotel room, eat hot food and change into dry clothes. The following morning, with an air of anticipation, they turn themselves in to the police. They are processed, then join about two dozen other North Koreans in holding cells.

It is a muggy day. In two of the cells, women and children – including the little sister who got the Barbie and an infant who has just started walking – fan themselves on mats on the floor and eat sunflower seeds. The pink bars have been turned into a makeshift washing line, and the girl has hung her doll’s dress on it.

A third cell contains a handful of men and the wannabe computer nerd.

Once there is a busload of them, as more North Koreans arrive nearly every day, they’ll be driven 12-plus hours to Bangkok.

The escapees say they have been focused on this moment: on the moment they would get to the safety of this humid and smelly cell; the moment the South Korean bureaucracy would whir into action.

It was the experience of crossing back and forth into China, unrelentingly capitalist China, that made the fisherman decide to flee from North Korea. He was earning a good living, plying the seas as his official job and transferring money across the border as his unofficial one. But seeing how Chinese people lived and listening to South Korean news on a radio he’d bought across the border had opened his eyes.

“I realised that what we were told by our media was all lies,” he says, the night before they surrender to police.

For the 50-year-old woman from the port town of Nampo, it was the fear of being repatriated to North Korea again – she’d just spent 2½ years in a re-education camp – that made her carry on after she made it back to China.

For the 23-year-old school friends from the border city of Hyesan, being sold to Chinese men – knowingly or unknowingly – was the way to make money for their families.

“I knew I was going to be sold, but I was prepared to go,” says one, looking up from her smartphone.

Her friend, a hairdresser, had gone to China several months before. She thought she was going to work in a restaurant but instead was sold to a Chinese man for the equivalent of US$12,000.

For all these reasons and many more, North Koreans cross the river into China.

Untold thousands risk their lives to escape each year. Some live in hiding in China, some get caught and repatriated, and some – 1,418 last year – make it to safety in South Korea.

When Kim Jong-un came to power, at the end of 2011, at the age of 27, many North Koreans hoped he would usher in a new era of modernity and openness for the totalitarian state. That didn’t turn out to be the case.

Kim has ordered a merciless crackdown on the long border with China, and Beijing has stepped up its own vigilance. The flow of people has dropped markedly – but has not ceased.

A vast network of brokers, many of them defectors from North Korea themselves, arrange escape through a system that is now so well-oiled that, if everything goes smoothly, a North Korean can be in a Thai detention centre within 10 days and in South Korea within a month.

That’s if everything goes right.

After finding a broker, North Koreans who have earned money through private trading pay up front for their escape. Others promise to pay with the settlement money they receive after arriving in South Korea. A lucky few have their escapes financed by Christian organisations.

The group containing the fisherman was rescued by Now Action and Unity for Human Rights, an organisation led by Ji Seong-ho, himself a North Korean who escaped. Ji’s outfit arranged to pay US$2,000 to get each member of the group out. Contacting a broker directly would have cost double that, he says.

The group crossed the river into China at night to find two cars waiting to take them to two safe houses – just as their broker had said they would.

“By the time we arrived at the house, it was getting light outside,” says a 42-year-old housewife. “We stayed there for three days, just eating and sleeping and watching Chinese TV until it was time to go.”

They were going to take a new route, through Vietnam rather than directly through Laos, because Chinese authorities had become more aggressive near the Laotian border.

“I was worried that we were being used as guinea pigs on the route. But if we were going to die, we were going to die,” the fisherman says. “We had already decided to kill ourselves rather than be sent back to North Korea.”

The group was then put onto the first of many buses for a 17-hour journey. “That was nothing – we spent more than 80 hours on buses in China,” the housewife says, with a laugh.

Being on a bus was dangerous. If Chinese police boarded to check their documents, the North Koreans would have been caught.

“We didn’t sit together, and we didn’t speak to each other while we were on the bus,” the housewife says. “Nobody bothered us because they thought we were sleeping the whole time.”

These escapes are usually coordinated by someone in Seoul managing the tricky logistics.

“We have to know the exact locations of checkpoints. We need to be able to tell them where to wait and when to cross,” says Kim Sang-hun, a Seoul-based Christian activist who helps North Koreans escape. “They can be arrested anywhere at any time, and the situation is going to be very bad for them. So to bring them to safety, we have to know the local bureaucracy and find a way to get around it.”

Yet this was the easy leg of their journey. Many North Koreans speak some Chinese, either through having lived in China or by trading with the Chinese, and their similar looks mean they can blend in with the local population.

When they got to the bus station closest to the border with Vietnam, the atmosphere changed. Police were patrolling the border in force, so their guides told them to take cover and then be prepared to run through the dark.

Hiding between buildings, waiting for their moment to cross, the North Koreans were being as still as they could be. The guides were gesturing at them not to move, they say. They didn’t need to have a common language – their body language spoke volumes. When the moment came, they ran. And they were across.

The hardest part was still to come. After several more bus and car rides through Vietnam, the North Koreans had to hike through the mountains along the border with Laos, through torrential rain.

“Every step of the escape is hard and dangerous – hiking mountains, changing methods of transportation and crossing borders,” Ji says. “Because they’re so tense, some fall ill during or after the escape.”

The journey is especially onerous for children, the elderly and the disabled. Mothers sometimes give their children sleeping pills so they won’t cry and give them up, Ji says.

Three men with flashlights were waiting to lead the group over the mountain paths. It was raining hard and they were all soaked through. The paths were slippery and treacherous. It was pitch black.

“We were told we were supposed to go over two mountains, but I think it was three,” says a young mother who left her four-year-old daughter behind in China while she made the escape. “It was really hard, and I was so scared I thought I was going to die from fear.”

The woman from Nampo says the border crossings were the most terrifying part.

“I kept thinking: ‘What would happen if I get caught now?’” she says. “If I was repatriated again, I knew that it would be the end of my life.”

They did make it into Laos, and there was another car waiting for them at the border. The driver’s nerves put them on edge. He was afraid of being stopped by the police with the North Koreans in his car, and his fear was contagious.

Most unnerving of all was the reality of being so close to safety but still not quite there. “I kept thinking: ‘Imagine if I made it this far and then I got caught in Laos,’” the young mother says.

Just four hours to the Mekong River and, across it: Thailand.

Their clothes still wet from the mountain crossing, the group was dropped on the river bank in the pouring rain. There, they waited in the darkness until it was time to cross.

At 3:30am, they got into one of the long boats that navigate the Mekong. The heavy rains had made the river high and fast, and they were dropped more than 30km downstream from where they were supposed to go ashore.

“There was nobody around, nobody waiting for us,” the housewife says. “Up until that time, everything had worked perfectly.”

But for the fisherman, it didn’t matter: “I was so relieved to be in Thailand. I sat by the river and smoked some cigarettes.”

Ji, the man waiting upstream for them, started out on a frantic, hours-long search. He heard from the coordinator in Seoul that they’d crossed and realised they’d missed their drop point, but he didn’t know where they were. And they, not being able to read Thai, didn’t know where they were, either.

Luckily, as one of the women in the group had a Chinese mobile phone, Ji eventually found them and took them to the nearby hotel, where a hot shower and dry clothes awaited them.

That Saturday night, before they turn themselves in at the police station, they have a celebration. They push back the beds in the hotel room, and the housewife cleans the tiled floor. They sit crossed-legged and eat sticky rice, grilled fish, fried chicken and banana chips, all washed down with large cans of Chang, a Thai beer.

The eight-year-old plays with a reporter’s phone, delighting in photo filters that give her bunny ears or a crown of flowers.

Not far to South Korea now.

Yoonjung Seo contributed to this report.

The Washington Post