Almighty God vs the Red Dragon: It sounds like a fantasy action film, but it is in fact a real and disturbing struggle in China. The most vivid case involves a group of people who beat a stranger to death in a fast food restaurant. They said they had no choice because the victim was a 'demon'. The killers are fanatical followers of the Church of the Almighty God, a Christian doomsday cult which claims millions of members across China and pledges to overthrow the Chinese Communist Party - which it calls the Great Red Dragon. Gracie uses her fluent Chinese to gain access to families of those caught up in the cult, including a man who infiltrated it to save his wife.

Produced by Becky Lipscombe