Queen Isabella, wife to Edward II of England, has been dispatched to France in an attempt to bring about peace between the two countries, and Sir Baldwin de Furnshill must accompany her with his friend Simon Puttock. But the day after their arrival, a servant is found murdered, with Baldwin's dagger lying next to the body.
The first message sent to Tom Thorne's phone was just a picture - the blurred image of a man's face, but Thorne had seen enough dead bodies to know that the man was no longer alive. But who was he? Who sent the photograph? And why? While the technical experts attempt to trace the sender, Thorne searches the bulletins for a reported death that matches the photograph. Then another picture arrives.