The North Korean term refers to homeless children, fending for themselves without the support of family or state. The word traces it roots back to the aftermath of the Korean War, an imaginative pronunciation of the Russian word "kochevyi," meaning "wandering," and referring to those displaced by the 1950-53 conflict.

During the 1990s, North Korea was hit by several years of famine as disastrous harvests laid waste to the land, killing hundreds of thousands, according to conservative estimates. The country's social safety net was reduced to tatters. Families fell apart. And flower swallows re-emerged in large numbers.

Although conditions today are much better, North Korea remains desperately poor. Food is in short supply for a large portion of the population -- and kkot-jebi are still very much in existence.

The Reveal

North Korea is one of the most secretive societies in the world. When a CNN team recently visited, our entire schedule was arranged by our official government hosts. Our "minders" accompanied us on every shoot. We had put in certain requests, but we never knew more than a few hours in advance what the next item on our itinerary would be.

When we were told to go to a meeting room at our hotel one afternoon, we had no idea who was going to be behind the doors, just something to do with the reality of defectors.

When we walked through the doors and saw eight young people sitting on one side of a huge round conference table, we immediately knew who we were to meet.

'Human Scum'

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In early summer 2013, the world's media cried foul over the repatriation of a group of nine North Korea children, then aged between 14 and 19, from Laos. They had been picked up by border security as they were being smuggled from China into Laos by South Korean missionaries, in the hope of getting them resettled in South Korea.

Pyongyang is not shy about its hatred of defectors. It refers to them in official media as "human scum" and accuses them of criminal acts, lying about their own country for fame and money and abandoning their own families.

The decision to return the children was widely condemned. Dire predictions were made about their fate: The children were being sent back to prison; they would face a lifetime of retribution and could even be executed.

But here in this room, nearly two years after their return, these former kkot-jebi appear transformed. Four young men dressed in the blue blazers of university students and two boys and two girls in secondary school uniforms, all sat waiting to answer our questions. The ninth member of the group was in a university further away from Pyongyang and could not be brought in at short notice.

Leaving home

They were all children between the ages of 12 and 17 when they crossed into China, separately or in small groups. They only met after they arrived at the missionaries' house.

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We asked why they left -- it was an uncomfortable opening question.

"We were young," said 17-year-old Ri Gwang Hyok. "We just went to China for fun."

Pressed for more detail, Mun Chol, 21, admitted: "Frankly, we had some family difficulties. We had been through a period in our history we call 'the arduous march (the years of famine).' We were not living well. I was young and naive. We were living by the Amnok river, which is at the border. I meant to return home. I was curious."

We then asked how many of them had experienced hunger before they left.

Four of the eight raised their hands.

"It was winter. We had preserved food during autumn. But it wasn't enough. Our family was too large," explained Pak Kwang Hyok, 19.

Once in China, the children were brought to a house in the border town of Dandong, looked after by a South Korean missionary CNN has called M.J. in previous reports , along with his wife. There, according to M.J., the starving children were transformed. According to the youngsters now, the picture was not so rosy. They said they were kept in the house for a year and a half.

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"The missionary lectured us about freedom," recalled Mun Chol. "But we weren't given any freedom. He forced us to study God and memorize religious books.

"Of course, the food was good," he added, "but that was our only pleasure. When you have food things seem OK, but a kid needs more than that."

Following our encounter with the students, CNN contacted M.J., who asked about their well-being. He says he misses them.

While hesitant to say much out of fear for their safety, he insists the students needed his help after fleeing North Korea.

Detained in Laos

China is a historical ally of North Korea, and North Koreans found illegally in the country face deportation if caught. After a year and a half, the missionary decided to move the children to a third country. He chose Laos, on China's southwestern border, from where he hoped he could get them to South Korea.

After a harrowing night trek for four hours through the hilly border region, the party were picked up by Laotian police and detained.

When they were told they would be sent back to North Korea they were terrified.

"The missionary said we would be killed if we went back," said Mun Chol. "He told us our families had been killed because we had left our homes."

Return of the prodigals

But instead of being punished, they tell us they received special treatment, extra tuition to make up for three years of missed schooling, and are now studying in the best educational establishments in the capital.

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"I was scared," admitted Pak Gwang Hyok. "I had left my home with a guilty conscience and spent time abroad. We had betrayed our country. I thought we would be punished. But now we are studying in the best universities in Pyongyang. Our fears were pretty foolish."

Soon after their return, the children appeared on North Korean television to denounce their enticement to defect by South Koreans. Now , more than a year later, they are again on display. They have become poster children for the "benevolence and forgiveness" of the North Korean authorities.

There is a huge difference between their lives when they left for China and now. "I feel like a pauper who has become a prince," said Ri Gwang Hyok.

But their families have not joined them in Pyongyang, the showcase capital. They remain in the poor border areas and their lives have not changed.

When he thinks about what might have happened if he had made it to South Korea, Mun Chol said, "If I had made it, I could have become a traitor -- a bad guy who deserts his family.

"I could have gone down in history as one of the 'scum of the earth.'"