When thirteen-year-old Matt disappears on his way home from school, his mother Rachel refuses to believe he is simply gone.Everyone tells her to let go. The police have no answers. Her friends think she's spiralling. Even her husband, Dom, seems to want her to stop asking questions.But Rachel won't give up. As she begins to uncover links between Matt's disappearance and a string of other missing children, a pattern begins to emerge. Then she finds the coded message Matt lef...