Immunologist Dr. Jessica Shepard travels to Paris at the urging of her friend, Tom Martine, an investigative journalist seeking information on French industrialist, Frédéric Averi. Tom is concerned that Averi's quest for profits may be damaging those dependent on the accuracy of his genetic testing laboratory.

While there, Jessica also plans to reconnect with former admirer Canadian narcotics detective Alain Raynaud, in Paris visiting his teenage daughter, who happens to be interning at Averi's private art museum. When a museum employee dies, Jessica and Alain must once again team up to solve the crime. Their journey takes them from Paris to a château in the Loire Valley and on to the diamond center of Antwerp.

Along the way, they cross paths with Averi but also a rare books seller, an analytical accountant, a Belgian diamond dealer and art connoisseur, and a seasoned French detective. Together, Jessica and Alain work to solve a mystery and unravel how all of these unique individuals around the world relate back to an unsolved murder.