Fifteen-year-old Clara Dune has a secret. She suspects she's adopted, but she's afraid to discuss it with her father, who recently moved the family to St. Augustine, Florida to complete an archaeological dig that's tied to secrets of his own. He distracts her by giving her an old book that tells the story of a saintly Augustine pitted against a wicked Faustus. Strangely, sparks fly from the book's illustrated pages as a battle between good and evil comes to life. And Clara suddenly finds herself in the middle of an ancient feud. Shortly after, a solar eclipse ominously cloaks her new hometown in darkness, and her father entrusts her with his greatest archaeological find ever: a powerful eighth-century Asturian relic from northern Spain. She confides only in her friend Jia Zhilan - and the boy she secretly loves, Mingo Santos - because her world quickly grows darker as malevolent forces conspire to burn her alive. Instead of relinquishing the artifact, Clara vows to protect it. Otherwise, St. Augustine will be destroyed. During this fiery hero's journey, Clara learns that she has a profound calling on her life that she can't ignore. It's one that places her at odds with a pyromaniac Spaniard - and his master, the diabolical Faustus, whose purpose is to take as many souls to hell with him as he can. Will Clara Dune survive this trial by fire to save her city - and her own soul?