Twin sisters Keziah and Tilly Lovell are identical in every way, except that Tilly hasn't grown a single inch since she was five. Then at the age of 15 the girls are sold to a mysterious Italian known as 'Captain'. Theo is an orphan, raised by his grandfather. Resenting his grandson for his mother's death in childbirth, Theo is forced to leave home without a penny to his name when he remarries, and a new heir is produced. Unable to train to be a doctor as he'd hoped, Theo finds employment in Dr Summerwell's Museum of Anatomy in London, and here he meets Captain and his theatrical 'family' of performers, freaks and outcasts. But it is Theo's fascination with Tilly and Keziah that will lead all of them into a web of dark deceits, exposing the darkest secrets and threatening everything they know . . .