When Chrissie was eight, she killed a child. Fifteen years later, she has one of her own.I killed a little boy today. Held my hands around his throat, felt his blood pump hard against my thumbs. He wriggled and kicked and one of his knees caught me in the belly, a sharp lasso of pain. I roared. I squeezed. Sweat made it slippy between our skins but I didn't let go, pressed and pressed until my nails were white. It was easier than I thought it would be. Chrissie is eight years old, and she has just killed a two-year-old boy. Her playmates are tearful and their mothers are terrified, keeping them locked up indoors.Chrissie knows how to steal sweets from the shop without getting caught, the best hiding place for hide-and-seek, the perfect wall for handstands. Now she has a new secret. It gives her a fizzing, sherbet feeling in her belly. She doesn't get to feel power like this at home, where food is scarce and attention scarcer.Fifteen years later, Julia is working in a fish and chip shop and trying to mother her five-year-old daughter, Molly. She is always worried - about affording food and school shoes, about what the other mothers think of her. Most of all she worries that the social services are about to take Molly away. That's when the phone calls begin. Julia is too afraid to answer, because it's clear the caller knows the truth - that Julia is Chrissie, living under the new name given to her when she was released from prison eight years before.Julia wants to give Molly the childhood she was denied, and that means leaving Chrissie in the past. But Chrissie doesn't want to be left.