Just when fifteen-year-old Bobby Pendragon thinks he understands his purpose as a Traveler -- to save the territories of Halla from the evil Saint Dane -- the rules are beginning to change. A plague has found its way from Cloral to Eelong, the latest territory Bobby has arrived on in pursuit of Saint Dane. So now Bobby must make a difficult choice: Does he follow the rules his uncle Press taught him? Or does he break the rules, putting not only his onw life at risk, but also the lives of his friends and ultimately, the entire human race?