When Charity is offered a post as governess in the Trevelyan household, she sees it as a welcome escape from her dreary life as the adopted daughter of the Reverend Palfrey. But her first sighting of Morwennan House fills her with an inexplicable sense of foreboding, and her fear is compounded by her first encounter with Francis Trevelyan and his strange sister Selena. Yet her charge, little motherless Charlotte, is an enchanting child who responds to Charity's affectionate nature, and there is Tom Stanton, a business colleague of Francis', whose good looks and honest charm awaken Charity's romantic interest. Soon, though, Charity realises that Morwennan is the headquarters of a dangerous smuggling operation, and a series of disturbing incidents add to her growing conviction that there are other, darker secrets lurking beneath the surface.