Aleksandra Daniels hasn't set foot in the quiet seaside town of Bellamy Bay, North Carolina in over twenty years. Ever since her mother's tragic death, her father has mysteriously forbidden her from visiting her aunt and cousins. But on a whim, Alex accepts an invitation to visit her estranged relatives and to help them in their family business: an herbal apothecary known for its remarkably potent teas, salves, and folk remedies.

Bellamy Bay doesn't look like trouble, but this is a town that harbors dark secrets. Alex discovers that her own family is at the center of salacious town gossip, and that they are rumored to be magical healers descended from mermaids. She brushes this off as nonsense until a local is poisoned and her aunt Lidia is arrested for the crime. Alex is certain Lidia is being framed, and she resolves to find out why.

Alex's investigation unearths stories that some have gone to desperate lengths to conceal: forbidden affairs, family rivalries, and the truth about Alex's own ancestry. And when the case turns deadly, Alex learns that not only are these secrets worth hiding, but they may even be worth killing for.