Florence's father finds his old friend dead and calls her. Florence and Captain Verlay investigate the murder and try to find the connection with Camille Claudel.

At the Louvre Museum, a Eugène Delacroix enthusiast is killed after having admired one of the artist's works. Simon is the sole witness, a teenager with a quite extraordinary memory. Without having seen the murderer's face, his hypermnesia might still enable an identification. The youngster's life is now in danger.