North Korea took her name, stripped her clothes and shaved her hair. But there was one thing they couldn't take from "Prisoner 42": her faith in Jesus.

She survived what seemed like a death sentence after fleeing to China during a famine to feed her family. Watchdog organization Open Doors USA estimates she was one of 250,000 imprisoned North Koreans—50,000 of whom are political prisoners jailed for their Christian faith. She spent one year in solitary confinement and was released after two years of hard labor.

North Korea has been the No. 1 persecutor of Christians on the group's annual list for 18 years now. Open Doors was hopeful that diplomatic efforts -- including the 2018 Winter Olympics and the Trump-Kim summit -- would mean easing pressure and violence against Christians. But that has not been the case.

Christ followers are still seen as a "threat" to the Kim family's ideology and quickly erased from society either by death, detention centers, re-education camps, or maximum-security hard labor prison campus known as Kwan-li-so.

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In an interview with Open Doors, "42" recounted how each morning when they would call for her, she would crawl out of a door flap -- typically used for dogs or cats -- and keep her head bowed low because she was not allowed to make eye contact with the guards. Then for an hour, they would ask her the same questions: "Why were you in China? Who did you meet? Did you go to church? Did you have a Bible? Did you meet any South Koreans? Are you a Christian?"

She said she had to lie to stay alive.

"Am I a Christian? Yes. I love Jesus. But I deny it. If I admit that I was helped by Chinese Christians, I will be killed, either quickly or slowly," she said. "They will murder me in this North Korean prison. Every day, I’m beaten and kicked—it hurts the most when they hit my ears. My ears ring for hours, sometimes days."

She said in her year in solitary confinement, she was trapped in a cold cell and never saw sunlight or a single soul.

"I spent one year in prison, and for one year my skin didn’t touch a single ray of sunlight," she said.

So she prayed and sang a song she wrote in her head -- but never out loud.

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"It has been a year now. I don’t know how long I will survive in this place," she wrote. "One day they will call me, and I won’t move. I will have died here in a North Korean prison. They will dispose of my body, and the first new prisoner that comes in will be 'Prisoner 42.' They will wear my clothes."

But one day she appeared in court, where she officially divorced her husband, against her will but for his sake and their children. They found her not guilty of being a Christian. Instead, she was sentenced to four years at a re-education camp.

A women's prison at the border of North Korea at Dandong.

A women's prison at the border of North Korea at Dandong. (Open Doors USA)

In between working 12 hour days, she became sick and had to stay in the barracks. But it was in there she saw a woman praying in tongues under a blanket.

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"Inside this North Korean prison, we wound up forming a secret church. When we met and felt safe enough, we prayed the Lord’s Prayer and the Apostles’ Creed," she said. "She was actually much braver than I was. She spoke to others about Christ as well."

But one day a car came and took her away. As for "Prisoner 42," she was released after two years.

A map of some of the prisons Open Doors believes are still operating. Some have closed and others have expanded, according to the group.

A map of some of the prisons Open Doors believes are still operating. Some have closed and others have expanded, according to the group. (Open Doors USA)

She told Open Doors the first thing she plans to do is find her husband and children.

"We haven’t seen each other in years," she said. "But God has watched over me here in this North Korean prison, and I pray and believe that he also watches over my family every second of every minute of every hour of every day."

She added: "I need to tell them about this loving God."

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You can read her full story here.