Dublin, 1816. A young nursemaid conceals a pregnancy and then murders her new-born in the home of the Neshams, a prominent family in a radical Christian sect known as the Brethren. Rumours swirl about the identity of the child's father, but before an inquest can be held, the maid is found dead after an apparent suicide. When Abigail Lawless, the 18-year-old daughter of the coroner, by chance discovers a message from the maid's seducer, she sets out to discover the truth.