Plot

After an attack renders her blind, Ellen Ashland withdraws from the world to recover. But soon she plunges into paranoia, unable to convince anyone that her assailant has returned to terrorize her by hiding in plain sight.

Following a brutal attack, violinist Ellen Ashland (Madelaine Petsch) is left blind. Clayton (Alexander Koch) is hired to care for her and she begins to adjust to life without her sight. One night, Ellen hears a distressed woman's voice; she initially believes the woman is in her apartment but then realizes the noise is coming through the vent. The following morning, her neighbour shows up and introduces herself as Lana.

As time goes on, Ellen grows suspicious of Lana. When she touches Lana's face, she feels a wound with stitches and is alarmed. Lana reacts by warning Ellen to trust no one and then flees Ellen's apartment upon the arrival of her abusive husband, Russo. Ellen contacts Detective Bryce who sends Officer Neiman to check on Lana; he confirms she is okay and does not have any recent wounds. Ellen expresses her concerns to Clayton who starts to show a romantic interest in Ellen, but when he confesses his feelings, she turns him down.

When Clayton leaves the apartment one afternoon, another person enters and attacks Ellen. She manages to dial 911 before she passes out. She is awaken by a paramedic and Detective Bryce who reassures her that after Clayton left her apartment, nobody else entered. Detective Bryce confirms to Ellen that her friend Sasha, who was having an affair with Ellen's ex-husband, is the prime suspect in Ellen's attack. Feeling alone and unsure of anyone, Ellen decides to commit suicide. She writes letters to her brother, Sasha, and Clayton, and then jumps from her apartment balcony.

Ellen wakes up on the floor of a soundproof room and quickly realizes the apartment she was staying in was fake, and all of the noises "outside" were coming from a speaker system. She explores the hallway only to find she cannot escape. Ellen goes to Lana for help, who tells her that this is home. Clayton then arrives to cook Ellen dinner and she realizes all of the people she has interacted with since her attack - the doctors, the detective, the paramedic, Russo - were all Clayton, dressed up differently. Ellen knocks Clayton unconscious and finds Lana who reveals she is Clayton's sister and she helped him kidnap Ellen. She then tells Ellen their only hope of escape is by using the hidden vent in Clayton's room.

Clayton finds and once again captures Ellen. He confesses that after his mother's death, his father kept him captive in the basement for three years, during which time Lana played Ellen's music for him, thus resulting in his obsession. Ellen tries to escape via the vent and finds a vial, which she realizes is the same substance that was used in her attack that made her lose her sight. She finds her way back to her apartment, chased by Clayton, and sprays the substance in his face. Upon seeing Clayton disabled, Lana guides Ellen to an exit into the outside world.

Six months later, Ellen prepares to go on stage to the sound of an elated crowd, as an assistant asks her if she needs any help.

(copied from Wikipedia)