In the fourth and final book in the Before Watson series, Sherlock Holmes and his companion and assistant, Dr. Poppy Stamford, embark on their greatest adventure yet. They are charged with solving not one case but three. One involves bogus charges against Poppy's former stable boy. The second is their attempt to stop a wave of crime perpetrated by the Elephant Gang, the famous and ruthless girls' gang that terrorized London in the nineteenth century. The third is an investigation into who burglarized the brothel owned by Maggie May, a mysterious woman with a keen mind and a treasure trove of secrets. During this time, Poppy also faces great losses and the promise of a new life - if she can bring herself to give up her quest to capture Sherlock's intransigent heart.