When Tristan receives a cryptic message requesting help, he and Simon must come to the aid of Quan of the White Phoenix. Someone has stolen the Holy Grail and the Order of Calyx--the group tasked with keeping it safe from abuse, and humanity is looking at the Golden Circle. With time running out, Tristan and Simon must find the Cup, return it where it belongs, and confront the thief, who is closer than anyone imagines, before the Order mobilizes and destroys the Golden Circle.