Josef Fritzl was a 73-year-old retired engineer in Austria. He seemed to be living a normal life with his wife, Rosemarie, and their family--though one daughter, Elisabeth, had decades earlier been "lost" to a religious cult. Throughout the years, three of Elisabeth's children mysteriously appeared on the Fritzls' doorstep; Josef and Rosemarie raised them as their own. But only Josef knew the truth about Elisabeth's disappearance...

For twenty-seven years, Josef had imprisoned and molested Elisabeth in his man-made basement dungeon, complete with sound-proof paneling and...