ALEXANDRA GLADE (POV), a vengeful and bloodthirsty vampire hunter, discovers a terrifying secret: the origin of vampirism, the biblical figure, CAIN. She’s faced with her deadliest mission, tracking two vampires, MASON and NIKOLAS, who uncover that true source of evil. They plot to kill Cain to gain his power. She deals with a terrible decision knowing that mankind’s existence actually hangs on Cain’s survival thanks to God’s covenant with Cain as written in the book of Genesis.
With the help of a young college student, MARCUS, Alexandra and her comrade KYAN discover a secret book revealing the truth about Cain and then realize the danger in keeping the book in their hands, knowing vampires stalk them for it. Mason and Nikolas apprehend Marcus along with the book, leaving Alexandra and her team of hunters alone to face the evil.
Mason and Nikolas find Cain and free him from an eternal sleep, leaving Alexandra with her horrible choice: save Cain, allowing a true child of Satan to possibly damn the world to agony; or allow Cain’s death, ending mankind. Alexandra slaughters Mason and Nikolas, saving Cain’s life, but at the greatest risk: the antichrist’s reign over the world. Deep within the ancient words of the book, Marcus realizes what he must do to save mankind from the likes of Cain.
He validates Cain, understanding him. According to the book of Genesis, Cain looked for God’s favor. He never received it. Marcus gives it. Marcus offers the earth to Cain in the same way Cain offered the work of the earth to God. That one act shatters all of Cain’s fury. That one selfless, trusting act—stops Cain from raging against the world.
As it stands, Cain lives. He vanishes without any knowledge of his whereabouts, but Alexandra knows he walks the earth. Whether or not Cain chooses to return to his eternal sleep—that itself is a mystery begging to be solved. She is faced with the decision to go on with her life as a vampire hunter. Holding onto the book that nearly ended all life on earth, naming it the “Cain Letters”, she lives on to face another set of fangs in her life as a hunter. Only this time not a hunter born of rage or blood. But of faith.