At a murder scene, Nick once again encounters the vampire Serena, who resents him for bringing her across in the 1920s. He strives to solve the crime, not realizing that she intends to use the chief suspect for the murder, Calvin Trilling, in her plans to regain mortality. According to ancient legend, a female vampire will become mortal if she bears a child; but for her to conceive, the father must be "a very special sort of man"—which Serena interprets to mean that he must have an extra Y chromosome, which Trilling has. Therefore, when Nick arrests him for murder, Serena contrives his escape from jail. This puts Nick in a quandary. Should he save Trilling, who will die at the climax of consummation? Or should he reconcile the wrong he did Serena by letting her continue with her attempt to become pregnant? (thetvdb.com)