Cults and Extreme Belief examines the "self-help" group NXIVM which has been catapulted into the spotlight with the recent arrest of its leader and a high-profile actress/member on charges of sex-trafficking and other crimes. The group also stands accused of drawing supporters down a path of destruction that includes near-starvation diets, forced branding, pseudo-slavery, and blackmail. Former members share harrowing experiences of manipulation and sexual violation, including Sarah Edmondson who sits down with Vargas to share new details of her ordeal inside the organization including being branded with a symbol that turned out to be the leader's initials.

Amy Bril recounts her childhood growing up in the Children of God, a group notorious for pedophilia and "religious" prostitution. Amy and others born and raised in the group are banding together to address a suicide epidemic among fellow survivors.