The cult with Bernard's dad being like a recruiter of sorts and that's how he met Bernard's mother, who gets manipulated into the cult, and they get married and have Bernard. Because of his father's position as a recruiter, Bernard's parents live ordinary (as ordinary as rich people are) lives in order to lure more people and don't really include Bernard when he's a child (because children are blabber mouths).
However, Bernard does get into the cult, as we know, and also gets out of it. When Bernard's mother finds out he was nearly sacrificed (she wasn't told on purpose, as they've always suspected she had a soft spot for her son as she was never as hard on him as Mr. Dowd), she tries to get out of the cult and reconcile with her son.
Meanwhile, Bernard finds out his parents are in the cult and his mother got lured in and rejoins (not without opposition from Tim) the cult undercover to find and help her. But, you know, they're all anonymous.
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So Mrs. Dowd tries to leave the cult undetected to rejoin her son while Bernard tries to infiltrate the cult undetected to rejoin his mother.
