Cassandra "Cassie" Nightingale is a mysterious, darkly beautiful woman. She 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.

As with the previous seven TV movies, the series continues the spirited life of newly widowed Cassie Nightingale, the good-hearted enchantress of Middleton, USA, with her now-teenage daughter Grace. When new neighbors, the Radfords, move in next door, they become suspicious of Cassie and her daughter.