As Middleton prepares for its annual Halloween Fall Festival, Cassie's neighbor Sam volunteers to set up a hay maze for it, hoping to bond with his son Nick. While Cassie tries to bring them closer together, she struggles to get her own family – daughter Grace, step-children Brandon and Lori and cousin Abigail – together to transform the Grey House into the town's most popular haunted attraction, under the watchful eye of Mayor Martha. Abigail is too busy campaigning against Stephanie in a heated competition for festival queen. Grace is being bullied at school as rumors circulate that she is a witch, prompting her to beg Cassie to put an end to their annual tradition. As Cassie welcomes a secretive stranger, Joseph, to the Grey House, she soon finds her intuition is no match for whatever is causing trouble for her family. While Brandon and Lori investigate Joseph's past, Cassie discovers a deeper connection that could put the whole community in danger.
A mysterious, darkly beautiful woman named Cassandra Nightingale moves into an old, abandoned house which is reputed to be haunted by its original owner, "The Grey Lady". The small community is divided in their opinion of her: Some want her to stay (especially widowed police chief Jake Russell and his two children), while others want her to leave. Through the course of the story, seemingly magical things happen, and the community attributes these occurrences to her. Everyone begins to wonder if she is really a witch.