"Cain's Secret" is the ninth volume of Tina Folsom's Scanguards Vampire series, telling the gripping story of the bodyguard Cain, who suffers from amnesia. When a mysterious stranger enters his life, Cain is confronted with the shocking truth: he is the target of an assassination and a powerful vampire king. As he tries to piece together his past, he learns about his engagement to the vampire Faye Duvall, who believes he is dead. Faye faces a difficult decision as she is ready to marry Cain's brother Abel out of loyalty to her clan. However, Cain's return not only brings back old feelings but also the threat from the assassin who is determined to destroy him. In a race against time, Cain must decide whether he can save his kingdom or his love for Faye. This captivating story combines elements of action, romance, and supernatural drama, drawing readers into a world full of intrigue and passion.