Dr. Anna Fox (Amy Adams), once a successful child psychologist, is now agoraphobic, with a drinking problem. Although she lives alone, she rents her basement apartment to a young man, David (Wyatt Russell). She's afraid to go outside, so she spends her time watching classic movies on television, drinking wine and occasionally, spying on her neighbors across the street — a father (Gary Oldman), mother (Julianne Moore) and their teenage son, Ethan (Fred Hechinger).
One night, she witnesses a disturbing act of violence, but when she reports it, no one believes her, not even the police.
Based on the novel of the same name by A.J. Finn.