North Korea is considered one of the most secretive countries in the world. It is officially an atheist state. The ruling party sees religion as a threat to its authority. Instead North Koreans are expected to show complete devotion to the ruling Kim family, who many view as godlike. There are believed to be a small number of Christians practicing in secret inside the hermit kingdom, but entire families can be sent to prison camps for practicing religion. Even owning a Bible can lead to detention or even death. There are an estimated 33,000 North Korean defectors living in South Korea. The exact number of North Korean Christians living in the south is unknown, but it is believed that a significant number of defectors now identify as Christians. BBC Correspondent Danny Vincent travels to the South Korean capital of Seoul to meet a family of defectors he first met a decade earlier while fleeing Northern China.