A 20th-century child intervenes in a 19th-century tragedy involving the ghost who has been her frequent companion and friend. Zoe lives with her grandparents; her vacant-eyed mother, who found Zoe's name on a crumbled local tombstone, turns up only for occasional unsatisfactory visits. From early childhood, Zoe plays with Zoe Louise, whom no one else can see; eventually, Zoe discovers that she can enter Zoe Louise's 100-years-ago world by going up the unused back stairs. There, Zoe becomes a ghost seen only by Zoe Louise. Finding an old newspaper account of Zoe Louise's death, Zoe is desperate to prevent it and eventually does so--whereupon all traces of the alternate past are obliterated and Zoe Louise's visits cease forever. With the telling use of sensory detail (the smell of chocolate and burning presages the dreadful fire that starts with a birthday cake) and arresting images (Zoe Louise begins appallingly to disintegrate as the time of her threatened death approaches), Conrad builds a spellbinding tale, with suspense and horror enough to make readers overlook any minor lapses of logic and forget to wonder just how the supernatural events have changed present-day Zoe. A satisfying thriller.