Ruth Butterham is young, poor and awaiting trial for murder. When Dorothea's charitable work leads her to Oakgate Prison, she finds herself drawn to Ruth, a teenage seamstress - and self-confessed murderess - who nurses a dark and uncanny secret. A secret that is leading her straight to the gallows. As Ruth reveals her disturbing past to Dorothea, the fates of these two women entwine, and with every revelation, a new layer of doubt is cast. Can Ruth be trusted? Is she mad, or a murderer?