"Auguste Lupa, Sherlock Holmes' putative son, must assume the role of his legendary father. In a small French town in the dark days of World War I, two French intelligence agents are searching for a mastermind assassin. One of the agents is killed and Lupa himself is suspected. Lupa not only uses his masterful powers of deduction to identify the real killer, but in a finale worthy of the master himself, lays bare an ingenious act of sabotage."