A dark secret lies hidden away in a far-off mountain for countless centuries. Will and his companions race after their captured friends in a desperate move to save the vampire race from extinction by the disease, or a horrible slavery through Stenson's control of the cure. The chase takes them to Constantinople where they meet up with new friends and foes, and find that their problems only skimmed the surface of the surprise that awaited them at the end of their journey. The fourth and final part to the four-part Young Adult paranormal adventure Blood Guardians series. The fourth book is set on the Euro-Asian continent of the 1830s.