From her first day as Personal Assistant to the celebrated Mina Appleton, Christine Butcher understands what's expected of her. Absolute loyalty, absolute discretion. For twenty years now, Christine has been a devoted servant, a silent witness to everything in Mina's life. Day after day, year after year, she's been there, invisible - absorbing the secrets floating around her, keeping them safe. Christine is trusted. But those years of loyalty and discretion come with a high price. And eventually Christine will pay. Yet it would be a mistake to underestimate her. Because as everyone is about to discover, there's a dangerous line between obedience and obsession.