Jo Frost, who has worked with children as a nanny for 28 years, investigates the cases of Britain's killer kids in order to answer whether children can be natural born killers.

Jo Frost, a modern day, tough-love "Mary Poppins" is placed with families in need of guidance or care. She spends an extended period of time with a family, observing their issues and then, using a series of her own tried-and-true methods, offer solutions. Problems can range from discipline to sloppiness or anything in between.