A woman kills herself for no apparent reason. A week later, her teenage son disappears. The vanished boy's uncle, Tim Underhill, returns to his home town of Millhaven to discover what he can. A madman known as the Sherman Park Killer has been haunting the neighbourhood, but Underhill believes that Mark's obsession with a local abandoned house is at the root of his disappearance. He fears that Mark came across its last and greatest secret - a lost girl, one who has coaxed Mark deeper and deeper into her mysterious domain. Only by following in their footsteps will Underhill uncover the shocking truth.