Cassie encourages Sam to keep his eyes open for mysteries to unlock, just as Martha unearths a long lost town charter with a hidden treasure map. Vincent heads out in search of the treasure, leading to an unexpected competition with another treasure seeker. Grace is hurt when she learns that Luke had been spying on Abigail for his aunt Donovan's mother, Dotty. Abigail continues to spar with her, until a crisis makes her reassess her relationship with Donovan. Meanwhile, Adam helps Stephanie with the launch of her food truck.
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.