When the enigmatic Sarah Tanner re-opens her Dining and Coffee Rooms soon after a disastrous fire, the gossips of Leather Lane grudgingly admit she has 'the luck of the devil'. Yet when a local butcher is falsely accused of a heinous offence, selling horse-meat, it seems her luck has run out...Drawn into an ever more dangerous series of confrontations with a gang of youths who seem determined to put an innocent man out of business, Sarah Tanner's own livelihood looks set for ruin into the bargain.But what links the persecution of a humble butcher with a certain Dr. Stead - a leading practitioner of the strange art of mesmerism - and a desperate plea from Sarah's former lover, the aristocrat Arthur DeSalle? As Mrs. Tanner investigates, she increasingly fears that the mesmerist, patronised by the highest in society, is a charlatan and his latest patient, the unwitting victim of a grotesque fraud. To preserve a family's honour, Sarah Tanner sets out upon a trail of suicide, murder, deception and deceit which stretches from the alleys of Leather Lane to the drawing-rooms of Mayfair. But the closer she gets to the truth, the more she seems to be putting herself in danger...