A good scary movie makes us afraid of its ghosts. A great one sees ghosts for what they are—specters of the past. That past can be horrific, filled with darkness we can never quite outrun. Ghosts can also be seductive, drawing us back to a past that we ought to have outgrown, teasing us with the idea that we can visit long-dead people and abandoned places, if only in shadow. We love ghost stories, perhaps, because we love the idea that there’s life beyond the grave, and that the past is never really gone. But the logic of story ensures that the gift of that reassurance comes with a price, and reminds us to be careful what we wish for.