You never know what's hiding behind your walls. Special Agent Emily Slate is a woman on a mission. Someone is sending her letters written in her dead mother's handwriting, and she's not about to stop until she finds out why. But when she receives a mysterious phone call from town where she grew up, Emily doesn't believe it's a coincidence. After all, where better to start tracking down the person who wrote the letters than in her own hometown? Except, when she arrives, she finds herself in the middle of a murder investigation. Initially a suspect, eventually she learns that the body of a missing seventeen-year-old girl was found in the walls of what used to be her childhood home. Not only that, but the victim was the sister of Emily's one-time best friend. With an entire town on edge, Emily isn't willing to leave the investigation up to the local cops. And as the secrets surrounding the girl's death begin to unravel, Emily finds herself in the crosshairs of a dangerous killer-one who has operated unchecked for over twenty years. Will she be able to find out who buried a body in the walls of her old home before anyone else goes missing? Or will the killer catch up with her first? It all comes back to The Girl in the Wall.