Hundreds of thousands of people are imprisoned without charge. It's not because they have committed a crime. It is because their relatives are believed to be critical of the regime and so they are punished. According to President Kim Jong Il, the bad blood and seed of any dissident must be rooted out down to three generations. Forced labour and starvation rations ensure that prisoners do not escape. Those who try to are publicly executed. But this is not the North Korea the government wants the world to see. The authorities go to great lengths to equip all foreign intruders with "minders" and monitor their every move.

The This World team were scrupulously guarded. The answers could only be found outside North Korea itself. Reporter, Olenka Frenkiel, hears testimonies from victims of the secret camps who have since fled to South Korea or the United States. And most shocking of all, she tracks down one of the perpetrators. Kwon Hyok, a former North Korean army intelligence officer, was also chief guard at "Prison Camp no. 22". For the first time on camera, he describes specially-made glass gas chambers used for human experimentation.
This World asks: if a deal is reached with North Korea about its nuclear weapons, should it be allowed to keep their gas chambers?