As ghost stories go, this one is not particularly gruesome or even scary, but it’s a good one nonetheless, and actually, it’s more of a haunted house story.  Every nine years a small iron door on a narrow street leads to a mansion occupied by a brother and sister who need to consume the soul of another person in order to maintain their immortality.  The intrepid but unwise people who enter the mansion are seeking those who have come before them and disappeared, but their curiosity or quest for closure seems to outweigh their good sense.  Part of the problem, of course, is that most of these seekers doubt that paranormal entities even exist and therefore lack the wariness that might protect them.  Plus, sometimes one of the sibling villains will inhabit a host’s body and masquerade as a helpful guide when in fact they are luring their unsuspecting prey into a trap.  Since each character, except the siblings, is a fleeting entity, I would say that this book is definitely not a character study, but David Mitchell’s writing never disappoints, even with the somewhat repetitive plot.  Each time a new victim starts up the Slade House stairs, I wanted to shout, “No, no, no, don’t go,” but each time some temptation eggs them on.  I have read that this novel is a sequel to The Bone Clocks, but since I do not remember that novel at all, I can assure you that this novel’s supernatural storyline stands on its own quite well, without the prequel.  It may not be a Mitchell’s masterpiece, but I certainly enjoyed the ride.