Ron Miscavige, father of the Church of Scientology leader David Miscavige, speaks exclusively to ABC News Anchor Dan Harris about his son's journey within Scientology starting when the family joined in 1970, and then his ultimate rise to current leader of the Church. It is a rare look inside Scientology told by someone who lived it for more than 40 years, 27 of them working for the Church's Sea Organization. Ron Miscavige's experience with and ultimate break from Scientology in 2012 is recounted in his new revealing memoir, "RUTHLESS: Scientology, My Son David Miscavige, and Me."

Could someone ever forgive a mom who would abandon not one but three newborn babies within blocks of each other over a five-year period? It is an incredible mystery that is solved right before viewers' eyes, as "20/20" teams up with renowned DNA detective and genetic genealogist CeCe Moore. Janet Barnicoat, one of those three baby foundlings, started her search as many do, with a Facebook post begging for clues about her biological family. The post went viral. After hearing about her story, Moore volunteered to help her on her search. What followed is a bewildering and shocking story, as Barnicot discovers she is one of three siblings abandoned by the same mother. But once the three are reunited, they go on a quest to find that mystery mom responsible for the unthinkable. It all culminates in a dramatic family confrontation and a series of startling confessions. Even Moore, with her 16 years of experience, had never seen a story like this one – telling Elizabeth Vargas, "It just blew my mind."