Paris: Tuesday 22nd August 1911 Incroyable! The very air of the city is charged with outrage. The Mona Lisa is missing from its place of honour in the Louvre. 'What audacious criminal, what mystifier, what manic collector, what insane lover, has committed this abduction?' ask the newspapers. Sherlock Holmes emerges from retirement to reveal the truth of the Affaire de La Joconde, a story of incompetence, villainy, greed, and international intrigue involving an Italian house painter, an American tycoon, and suave Argentinian con man the Marqués de Valfierno.