In 1922, young pianist and composer Olwen Trevelyan, troubled and sleepless over her inability to finish the final notes of her composition, falls to her death from the cliffs of Cornwall. 25 years on, Olwen has gained posthumous fame as a result of her tragic death and her haunting uncompleted composition 'The Dream of Olwen'. Her reclusive sister Julia (Sonia Dresdel), who has never come to terms with Olwen's death, becomes convinced that Olwen has returned when she meets an amnesiac woman who looks like her.

A wealthy French widow is poisoned in her home, Inspector Hanaud investigates..