When Sadie and Will Foust move their family to an idyllic small-town Maine, everything seems great. Until their neighbour Morgan Baines is found dead in her home. Sadie is determined to figure out what happened, as everyone's eyes turn to her. But while she's struggling to discover what happened, she's also hiding something that she can't let anyone find out. The Other Mrs. by Mary Kubica is full of surprises at every turn.