1906. Letty Ingram has travelled all the way to Singapore from her windswept Scottish home because she desperately needs help. The terrifying 'curse' that has plagued her since childhood now threatens to consume her. Only one person can free her from the demons that haunt her: the formidable Miss Cassidy. To find the answers, she must travel through worlds and time, from Victorian London to Paris's scandalous demimonde, into a realm of ancient spells, dark magic and the deadliest of evil spirits. But in trying to save Letty, will Miss Cassidy have to bargain with her own life?