When three-year-old Charlotte witnessed her mother's death and was left alone with the body, she began hearing the voice of a person living in the walls of her house. This voice comforted her as best it could, guiding her to call 9-1-1. Twenty five years later, Charlotte has returned with her own family to reconnect with this presence. The recent death of her son leaves her distracted and mourning, though, so she doesn't realize her daughter can hear this entity too.
