August 1787, the biennial art exhibition at the Louvre opens with a ghastly discovery. One of the paintings to be shown at the Salon of 1787, portraying a countess who had recently died, has been vandalized. The artist of the portrait, commissioned by her husband, an elderly count, becomes one of the suspects. The artists accuses a colleague who, however, shortly thereafter is stabbed to death.

     Lethal Beauty, a historical mystery novel, set mainly in Paris, is the fourth novel in the Anne Cartier series, following Mute Witness (2001), Black Gold (2002), and Noble Blood (2004). Anne Cartier is drawn to investigate the crime by her deaf friend Michou, a pupil of the murdered artist. Other suspects include an Italian art dealer, who may have known the countess too well and has reasons both to love and to hate her. At the heart of the mystery is a master extortionist ensnaring the participants. Anne, her husband Paul de Saint-Martin, and his adjutant Georges Charpentier pursue the investigation from the Lourvre's apartments and studios into the streets and sewers of Paris and beyond to the count's country estate near Fontainebleau. The chase comes to a climax in an art gallery.