Tricia realizes the intruder is Luke Strauss, the man whose voice she heard on Adrienne Hale's tapes. Under Ethan's accusations, Luke admits he was Adrienne's boyfriend but insists he did not kill her. He says he has been secretly staying in the empty house because he lost his job, his reputation, and his family support after being publicly treated like Adrienne's murderer.

Ethan presses a harsher theory: Luke returned to the house to remove Adrienne's body before anyone discovered it. Luke denies even knowing the corpse was there and says he only came to investigate after hearing shouting because Adrienne had vanished on a night when they were supposed to meet. Tricia is moved by Luke's anguish and believes he may be telling the truth, but Ethan refuses to trust him.

Because Ethan thinks Luke is still a threat, Ethan decides they must restrain him. Tricia gets duct tape from the desk so Ethan will not search it himself, and together they bind Luke's ankles and wrists while he begs them not to. Once Luke is secured on the couch in the office, Tricia feels temporary relief, though she is disturbed by Ethan's cold, commanding behavior.

After leaving Luke tied up, Ethan says he wants to leave the house immediately and go through the snow to the main road to get help or find phone reception. Tricia is terrified to be left alone, especially with Luke still in the house, and her fear is sharpened by thoughts of the baby she is carrying and her dependence on Ethan. Ethan promises to return within two hours and warns Tricia not to enter the room for any reason, but just before he leaves, both of them notice that the bookcase concealing the hidden room is standing open, suggesting someone or something has disturbed it.