London, 1884: Sidney Grice—London's foremost personal detective—is restless. Having filed his latest case under 'S' for 'Still To Be Solved', he has returned to his book, A Brief History of Doorstep Whitening in Preston, to await further inspiration. His ward, March Middleton, remains determined to uncover the truth. Geraldine Hockaday, the daughter of a respected Naval captain, was outraged on the murky streets of Limehouse. Yet her attacker is still on the loose. But then a chance encounter in an overcrowded cafe brings a new victim to light, and it seems clear March and Grice are on the trail of a serial offender. A trail that will lead them to the dining room of a Prussian Prince, the dingy hangout of an Armenian gangster, and the shadowy ruin of a once-loved family home, Steep House...