This episode investigates four cases in which girls and young women are held against their will, often for many years. We explore the brutality, cruelty and control imposed on their victims by some of the world's most twisted jailers, including: Wolfgang Priklopil, who kidnapped 10-year-old Natascha Kampusch, the notorious 'Black Panther' Donald Neilson who killed heiress Lesley Whittle, the monstrous Josef Fritzl who kept his own daughter in an underground dungeon for 24 years, fathering seven children with her, and sexual sadist Ariel Castro who imprisoned three girls as his sex slaves for 10 years.