A pair of adult twins share a consensual incestuous relationship (along with their mutual mistress). Throughout the book, blood-drinking (and at times, other kinds of bodily consumption) is a direct metaphor for possessive sex. This is initially portrayed as darkly romantic, and becomes disturbingly obsessive and abusive. There is no non-consensual sex, but there is lots of non-consensual sensual intimacy. It is also strongly implied that the act of repeatedly having one's blood drained creates a supernatural affection similar to Stockholm Syndrome. One character discusses her childhood relationship with her father in language that heavily implies incest. The father repeatedly drank his daughter's blood, making his wife jealous.