Son of Holmes — John T. Lescroart

THE TIME:
1915, World War I rages on.

THE PLACE:
Valence, France, a quiet backwater of gaslit streets and crowded cafes.

THE GAME
The search is on for the world's most dangerous assassin. Only one man can match wits with a criminal of such Moriarity-like cunning--and Sherlock Holmes is dead. But his illegitimate son, Auguste Lupa, is on hand to use his masterful powers of deduction--and the rest is elementary.