When detective Margot Cranston vacations in Montreal, a cruise ship sails into a crime-riddled nightmare. A ghastly ghost haunting an ancient lighthouse stirs trouble in the waters of the St. Lawrence River. Margot, her niece Amy, and her nephew Andy are ensnared in a weekend of trickery and intrigue that only an encounter with the phantom can resolve. Margot risks danger, deception, and her own death to unravel the secret of the St. Lawrence lighthouse.