We all would like to think that we're immune to being persuaded, but were that true, advertising wouldn't work, the best candidates would always get elected, and our personal relationships would always be equitable. On Belief examines why, with so much information available to us to dissuade us from joining harmful groups. I ask people who have had first hand experience with harmful groups and sects how they were seduced, how they were tricked, and how they got out.