It was crazy really, she had never met the woman, had no idea of her real name but she thought of her as a friend. Or, at least, the closest thing she had to a friend in Dublin. Struggling with a new baby, Yvonne turns to netmammy, an online forum for mothers, for support. Drawn into a world of new friends, she spends increasing amounts of time online and volunteers more and more information about herself. When one of her new friends goes offline, Yvonne thinks something is wrong, but dismisses her fears. After all, does she really know this woman? But when the body of a young woman with striking similarities to Yvonne's missing friend is found, Yvonne realises that they're all in terrifying danger. Can she persuade Sergeant Claire Boyle, herself about to go on maternity leave, to take her fears seriously?