A year ago, the town of Atom was shocked by the murder of a local man and his two daughters. The locals now refer to the place where the murders happened as the house on the hill. When a stranger called Felstar buys the house on the hill, the killings start to happen again. Sam and Scott, two teenage boys, have met Felstar and immediately dislike him. This is particularly unfortunate for Scott as his mother, Louise, has fallen in love with Felstar. Despite his protests, Louise continues her relationship with Felstar. Even Sam's father, the insecure Sheriff Newell thinks Felstar is a serial killer. The townsfolk are up in arms and Sheriff Newell is not sure he can cope. Sam and Scott resolve to act to protect their families and prove to Louise that Felstar is not the man she thinks he is.