In 1860, a 70 year old widow turned landlady named Mary Emsley was found dead in her own home, killed by a blow to the back of her head. What followed was a murder case that gripped the nation. The murder is the frame for the book; newspapers at the time were fascinated and furiously debated the character of the victim, potential suspects and the possible motives. During the police investigation there were several twists and dramatic discoveries and eventually, one of the last public executions at Newgate. Years later the case caught the attention of Arthur Conan Doyle, who was convinced that the wrong man had been convicted and executed.