It has served us well, this myth of Christ.' (Pope Leo X, 16th Century)Four masked horsemen, dressed as Knights Templar, storm an exhibition of Vatican treasures at the Metropolitan Museum of Art, stealing artefacts and beheading a security guard. Archaeologist Tess Chaykin sees their leader select a piece that turns out to be an ancient decoding device used by the Knights Templar. Consequently, she becomes involved in an investigation in pursuit of her former colleague, William Vance, whose obs