 Wilson's fifty-first book, it is about the remnants of a race of intergalactic vampires who are brought back from outer space and are inadvertently let loose on Earth.The titular space aliens are energy vampires, rather than the familiar stereotypical Earth vampires that suck blood and change into bats.They consume the "life force" by seducing living beings with a deadly kiss and also have the ability to take control of the willing host bodies of their victims.