"Yesterday morning, local boat-builder Mr Roger Trevithick was found dead at the foot of the cliffs on the Zennor Coast..."
When Stef Brightbay goes to visit her Aunt May in the village of Zennor in Cornwall, she expects to have an uneventful trip. But when her mother persuades her to research their family history and she begins to uncover a tragic event that took place there in 1812, she is determined to find out more. She also learns of the local folklore; the legend of Matthew Trewhella who was enticed to his death by a beautiful mermaid.
Why is her aunt so uncommunicative? What secret is being hidden by a strange local family who seem to want to put a stop to her investigation? And even more mysteriously, why are unusual things happening at her aunt's cottage?
With the help of sea-salt fisherman Arthur and his faithful chocolate Labrador, Stef pieces together the past and realises that a frightening parallel is unravelling in the present day. Will they be able to take action before it's too late?