Narrator: It usually begins quietly. There is no courtroom, no public trial, no verdict read aloud for a political case. Agents of the State Security Department, the Bowibu, come to a home, often before dawn, and a person is simply taken. What counts as a crime is almost unbearably small: criticizing the leader, making contact with South Korea, practising a religion, trying to defect, even folding a newspaper carelessly across the printed face of a Kim. And then there is the rule that gives the whole system its particular horror, called yeonjwaje, guilt by association. Under it, punishment reaches three generations. A grandfather's supposed offence can send his children and grandchildren behind the wire with him. Tens of thousands of people are held not for anything they did, but for a relative's act. Here's the part that stays with you. Detainees are often never told the charge against them, and never told how long they will serve. Many are simply held for life, with no sentence, no appeal, no end date. The family left behind is not told where their mother, their son, their brother has gone. The person is taken, and no one is told where.