Perris used to be an unremarkable middle-class suburb in southern California, full of streets of identically anonymous homes. But its inconspicuousness was blown when police received an extraordinary 911 call from a 17-year-old girl. She claimed she and her 12 brothers and sisters, who ranged in age from 29 to 3, had for years been held against their will in the family home. She said they had been chained up, tortured and starved. Worst of all, she accused her parents of being responsible for the abuse. Following the emergency call, police and welfare authorities raided the home and rescued the children. They also arrested the parents, David and Louise Turpin. As Liam Bartlett reports, the mistreatment the 13 Turpin children endured is now considered to be one of the worst cases of child neglect and abuse in American history. But even more shockingly, he discovers the shameful family secret that started this nightmare.