France in the 1910s... Loud mysterious crimes are taking place in the art world. The best detective in Paris, the brave Monsieur Lenoir, is entrusted to unravel them. He paints pictures and curls his mustache. And he is also a brilliant detective - Gabriel Lenoir. In May 1912, he was assigned to investigate the circumstances of the death of the daughter of the German ambassador. Relations between France and Germany are heating up to the limit. Only Monsieur Lenoir has the power to preserve the fragile peace in Europe. He gets down to business and... recognizes the deceased as the model who recently posed for him. Unheard of fun for the ambassador's daughter! What else is hidden behind the girl’s death?