Missing Child by Patricia MacDonald

Caitlin Eckhart's life starts falling apart after dropping her step-son Geordie at school. When the school calls later in the morning to question his non-attendance she frantically calls her husband, Noah, and other members of the family. As the search progresses, blame escalates and it appears that her past might catch up with her. A dark secret is uncovered. How is all this connected? A quick suspenseful read.