As Luca and Isolde continue their journey, their attraction grows with each passing day. Even as they try to remain focused on the mysteries they've been ordered to investigate, the tension between them builds. Then their budding, forbidden relationship is put on hold when a boy, Johann, and his army of children arrive in town. Johann claims to have divine orders to lead the children across Europe to the Holy Land, and the townspeople readily accept his claims. Luca wants to believe, but his training tells him to question everything. Though when Johann's prophecy begins to come true, Luca wonders if they have finally stumbled upon a real miracle. Yet even the greatest miracles have the potential for darkness...And the chaos that follows Johann is unlike anything Luca or Isolde could have imagined.