It's difficult to see where this fails to impress. The story isn't bad, two teenagers in a particular city where there are unexplained things occasionally happening. Urban legends seem to point at the thirteenth floor in the Mortagaine House as being somehow the focus of all the strangness. Bee and Dino are curious, interesting and strong teens who visit the floor and then work on seeing what they can do to keep themselves from being sucked into the strange. Sorry but Diane Wynne Jones does it better and creates a better sense of place and menace I just didn't get quite that sense of tension or other.