Following a family dispute, Janet moves out of the home she shares with her older sister, Lara and their single mother, Maddie. She moves into apartment 1303 on the thirteenth floor of a downtown Detroit apartment building. A 9-year-old neighbor, Emily, explains to Janet that a previous occupant of her new apartment killed herself. Strange things begin to occur in the apartment and when Janet appears bruised at work, she rebuffs concerns that her boyfriend, Mark, is abusing her and blames the marks on sleepwalking.