Madison "Maddie" Young (Kate Siegel), a young deaf author who lost her hearing after a bout of bacterial meningitis at age 13, is living inside a small cottage in the woods and surviving off the money from her books. Her friend and neighbor Sarah (Samantha Sloyan) visits her one evening and while walking home, is chased back to Maddie's cottage by a masked man (John Gallagher Jr.). Sarah bangs on the doors for help, but Maddie can't hear her cries as the masked man stabs her on the doorstep.
The man quickly realizes Maddie's ailment and uses it to his advantage. He sneaks into the house, takes her phone, and begins taking photos of her and sending them to her laptop to make her aware of his presence. As Maddie realizes she's being stalked, she locks herself inside the house as the man cuts the power and sabotages her car. Maddie writes that "she didn't see his face and won't tell anyone" on a window in lipstick and the man responds by revealing himself, so that Maddie has seen his face giving him a reason to kill her too. The man taunts Maddie by propping Sarah's body up against the window. Maddie tries distracting him with her car alarm and tries reaching outside for Sarah's phone from her body. The plan backfires and the man attacks, but she fights him off.
The pursuit continues as Maddie makes several attempts to escape, eventually climbing through a second story window onto the roof. Once on the roof, she tries distracting him and making a run for it but her plan fails when she doesn't fool him long enough and he begins firing a crossbow up at her, hitting her leg. As he's climbing up the side of the house to finish her off, she manages to knock him off the roof and take his crossbow in the process. Going back into the house, she tries frantically to load the crossbow as Sarah's boyfriend named John (Michael Trucco) arrives at the house looking for Sarah. The man confronts John, pretending that he is a police officer on a dispatch call to Maddie's residence. He pretends to call for back-up on John's phone as John gets more suspicious about him. John prepares to attack the man, but Maddie bangs on the glass which distracts John, and the man stabs him in the neck.
John uses his last bit of strength to put the man in a chokehold to give Maddie time to escape, but she knows that she can't make a run for it on her injured leg. John dies and the man recuperates while Maddie makes a decision to fight. She knows that she can't run on her leg due to blood loss and she can't hide because he has the advantage of being able to hear her and she can't hear him. She manages to load and shoot him with the crossbow but doesn't kill him. While getting back inside, her hand is caught in the door and the man breaks it. After he threatens to come in soon, she begins to taunt him for not coming in to fight her. He breaks into the house and Maddie types her last words and a description of her intruder on her laptop. She uses every last bit of strength and her heightened senses to fight him. After a brutal battle, the man begins choking her. On the verge of death, Maddie manages to grab a corkscrew and finally kills him by stabbing him in the neck. Calling 911, Maddie goes outside to sit on the porch with her cat and waits for the police to arrive.