On a humid summer day in Alabama, a mayor's wife turns up brutally murdered under a railroad bridge. Standing next to her body is fourteen-year-old Mason Hill, the autistic son of former Miss USA Genevieve Hill. The locals are quick to level their verdict on young Mason: he did it.

The town detective calls in local autism expert Casey Walker to consult on the case. At first, Casey tries to keep an open mind. But the more time she spends with Genevieve, the more her unease grows, and she suspects that Genevieve is doing more than just protecting her son.

Casey's misgivings surrounding Genevieve's story only intensify when she meets Savannah, Genevieve's nineteen-year-old daughter. Savannah, as it turns out, has some disturbing secrets of her own. But as Casey dives ever deeper into the Hill family dynamic, her search for the truth leads to another shocking murder--one that shatters her understanding of the human condition in ways she never imagined.