"Nathan Bishop is not quite like other kids. Today, we would say he had Aspbergers or autism but in 1979 their is no diagnosis for this condition and people mostly just find him weird and different. Nathan and his mother, a recently divorced pianist with money problems, have been invited by the mysterious Lady Grayer to come for a musical soirée to Slade House! Nathan's mother is very excited about the visit although a bit worried that Nathan will embarrass her.
After some trouble finding Slade House they find their way in through a small door in a brick wall and enter a beautiful garden where they meet the owner and a boy. Nathan plays with the boy in the garden as his mother disappears into the house with Lady Grayer (the owner) for some afternoon piano. To soothe his nerves for the visit, Nathan has stolen some Valium from his mother and therefore, unfortunately, he is not surprised when weird things starts happening.
These things are warning signs that young Nathan misses though... and he is tricked into entering Slade House where he goes up the stairs, one after the other. And you should never ever go up the stairs in Slade House. Not if you you want to come back out again. Every nine years, a new guest is invited into Slade House and every time, the house and its inhabitants look and act differently in order to set their trap and lure their victims into the attic. But who are they really and what is it that they want from their visitors...?"