Pyongyang, North Korea (CNN) The doors open and a prisoner is marched in by two stern-faced North Korean guards, their demeanor expressing authority and righteous disdain for the inmate.

In contrast, 60-year-old Canadian pastor Hyeon Soo Lim shuffles in the room. His close-shaven head, gray uniform and downcast eyes express meek submission.

Seeing him handled in such a manner is a shock, even though we were told exactly what would happen.

For 30 minutes before Lim's first conversation with foreign media, we tried to negotiate a straightforward interview for the pastor accused of trying to use religion to overthrow the atheistic North Korean regime. The authorities insisted that prisoner protocol, dour guards and all, was nonnegotiable.

The guards lead Lim to his seat on the far side of a massive conference table.

"Sit down!" one guard orders. Lim sits.

"Stand up!"

Pastor Lim rises without hesitation, as if he had been expecting the command.

"Sit down!" the first guard says again.

The pastor meekly obeys and the guards turn sharply and march out without a second glance. We are unsure if these theatrics are for our benefit or simply standard practice. The guards, we are told, will be standing outside the doors for the entire interview.

Signs of daily toil

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Lim's prison uniform bears the number 36. It is clean, but his shoes show scuffs and traces of soil -- signs perhaps of his daily work.

Since his trial in December, Lim has been held in a labor camp. He appears to be the only inmate. He has not seen any other prisoners. Lim works eight hours a day, six days a week, with rest breaks, digging holes for the planting of apple trees in the prison orchard.

There are always two guards watching over him. He is serving a life sentence of hard labor. He has no contact with the outside world.

It was difficult work at first, he says. But he has slowly gotten used to it and now comforts himself with the thought that the exercise is good for him. He looks healthy enough, though his loose fitting prison clothes make it hard to tell if he has lost weight.

We ask if there is anything he needs.

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"Nothing much, just a Bible. I have requested one, but it has not arrived yet," he says. "I also really need letters from my family. I have received letters twice from my family."

They also sent him snacks of dried fruit, his favorite.

The pastor tells us he has only been able to send one letter to his family -- through Swedish diplomats in Pyongyang. Sweden customarily performs such services on behalf of the United States, which has no diplomatic relations with North Korea.

Lim is desperate to get a reply. But a family spokesperson says, to her knowledge, they have not received the letter.

A routine humanitarian trip

A Canadian citizen who emigrated from South Korea in 1986, Lim is a minister at the 3,000-member Light Korean Presbyterian Church in Toronto. He has spent a lot of time in North Korea, taking more than 100 trips there, according to his family.

Lim's most recent visit came January 30, when he traveled there via China on what a family spokeswoman characterized as a routine humanitarian trip.

He planned to tend to aid projects established by his church in the northeastern city of Rajin, North Korea, including an orphanage, nursery and nursing home.

"It is this tremendous love for the people of the DPRK that motivated Mr. Lim to travel (there)," family spokeswoman Lisa Pak has said.

Sentenced to hard labor for life in December, Lim has not lost his faith. He continues to pray and asks his congregation to pray for him.

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But he says his views on the DPRK have changed a lot.

"I used to think they deified their leaders too much, but as I read the memoirs of both Kim Il Sung and Kim Jong Il, they never called themselves gods."

"Would you say your biggest crime was speaking badly about the supreme leaders of this country?" we ask.

"Yes, I think so," he replies.

"I hope I can go home some day," Lim says. "Nobody knows if I will ever go home, but that is my hope. I miss my family. I am longing to see them again, and my congregation."

He prays every day. He prays for reconciliation between the North and South, he says. He prays that no one will be in the same situation that he is now.

We invite Lim to record a message to his family, and tears well up as he looks toward our camera.

"I have realized so keenly how valuable my family is, how precious it is to me," he says. "Family is a precious gift from God. I would like to tell my family I love them so much."