Arson investigator Billy Nightingale and his brother-in-law, Officer Sebastian Bly, are called in to investigate a house fire that killed two young children. The discovery of a baby hiding underneath the porch put Billy and Sebastian on the trail of a murderous mother while Sebastian and his wife, Annie, raise baby Meredith without revealing her dangerous and frightening past. But the truth threatens their charmed family circle as Merry's biological mother returns to finish what she started.