Alex Harrison approaches the old abandoned mansion, the windows of which have recently been bricked up, in her neighborhood on Halloween. To her surprise, the house is inhabited by a young man named William. She finds herself attracted to him, and their relationship deepens. However, he is slightly off-putting, and she does not entirely trust him. As William draws her in deeper, other people become entangled in his web of lies. Connor Cartwright, Alex's peer and neighbor, begins to see that William has ulterior motives for Alex and attempts to get her away from William before his plan comes to fruition. However, Connor fails. As William's shadowy past begins to come to life and he begins to unravel, Alex tries and fails to distance herself from him.Through manipulation and deceit, William traps Alex alone with him inside the mansion, where she must fight against him for her life.