In the wake of a failed attempt to defeat the vampire Richelieu, Susan and her friends are weakened and divided. Raphael must set aside his animosity and join with his enigmatic sire Gabriel to discover a powerful weapon before Richelieu claims it. Meanwhile, Susan and her cousin Wendy translate a 12th century diary belonging to their ancestor, Carissa, to learn the origin of their family's connection with the vampires. As Carissa's story of love and betrayal unfolds, they discover the secrets of the present will only be revealed by solving the mysteries of the past.