The Disappearance of Susan Cox Powell unveils a shocking new theory that may explain why Susan disappeared.

Susan Powell was just 28 years-old when she vanished from her suburban home in West Valley City, Utah in 2009. Upon her disappearance, Susan's husband Josh Powell gave the police a strange alibi – claiming that after his wife went to bed, he took their sons Charlie, 4, and Braden, 2, on a spontaneous camping trip during a violent, winter blizzard. More than two years later, and after an unsuccessful police investigation, the unthinkable happened: Josh Powell took his own life and that of his two sons. The special follows investigative journalist Stephanie Bauer as she dissects Josh and Susan's marriage, taking a stark look at the topic of domestic violence and emotional abuse while revealing a complex Powell family dynamic – from the onset of her relationship with Josh, Susan became the object of desire for Josh's father, Steven Powell. The special unearths boxes of lurid videotapes shot by Steven Powell, vividly divulging an astonishing sexual obsession with his daughter-in-law.