The Guilty (2013)

DCI Maggie Brand leads the new investigation. Pregnant when Callum went missing, debilitating morning sickness had forced her to step down from the original investigation. Her son, Sam, was born only a few months after Callum disappeared. Now he's starting school and Maggie has to deal with her own feelings of loss, as she confronts the reality that her little boy is very different to the other children in his class. Driven by her obsession to discover what happened to Callum, Maggie leaves no stone unturned in piecing together the events of that fateful night.