The Case of the Missing Marquess — Nancy Springer

When Enola Holmes, much younger sister of detective Sherlock Holmes, discovers her mother has disappeared -- and on her fourteen birthday, to make matters worse -- she knows she alone can find her. Disguising herself as a grieving widow, Enola sets out to the heart of London to uncover her mother's whereabouts -- but not even the last name Holmes can prepare her for what awaits.

Suddenly involved in the kidnapping of the young Marquess of Basilwether, Enola must escape murderous villains, free the spoiled Marquess, and perhaps hardest of all, elude her shrewd older brother -- all while collecting clues to her mother's disappearance.

Infused with the voice and atmosphere of Victorian London's rat-infested streets, this suspenseful and witty novel brings mystery lovers the genre at its best.