After giving a concert at the Château d'Amboise, a virtuoso violinist is found murdered a few metres from Leonardo da Vinci's tomb, in a pose reminiscent of the Vitruvian Man, one of the artist's most famous drawings. The captain of the Orleans investigation unit, Alban Dutertre, returns to his hometown, where he has more than just fond memories, to conduct the investigation. He teams up with Sergeant Bérénice Amarillo, fifteen years his junior, a brilliant but shy police officer who is struggling to overcome the weight of an arrest that went wrong. Soon another murder occurs, also inspired by Leonardo da Vinci. If they want to catch the killer, Alban and Bérénice will have to solve a puzzle worthy of those the artist liked to construct...