Cordelia and her twin sister don't realize the mother who left them soon after their birth bequeathed them a dark bloodline. They're half vampire. Although human in most respects, they possess certain psychic gifts. A friend of their late father's, Karl, also a vampire, has been watching over their family for generations in honor of his love for their distant ancestor. When her sister is kidnapped and Cordelia must beg for help from Karl, she learns the truth about his vampirism and her own heritage. In the process, she and Karl form a blood bond that leads to deeper intimacy than either one could have anticipated.