Living in denial, the depressed, pill-popping child psychologist, Anna Fox (Amy Adams), has holed herself up in her eerily vacant, ill-lit Manhattan brownstone apartment for the past ten long months, separated from her husband and their eight-year-old daughter. While unsuccessfully grappling with agoraphobia and intense panic attacks, suddenly, the Russells; Alistair (Gary Oldman) and Jane (Julianne Moore) move in across the street, and brimming with curiosity, Anna decides to distract attention away from her problems by peeking into the lives of the unsuspecting new tenants. Then, one night, tensions flare, a deadly kitchen knife gleams in the dim light, and before long, someone ends up dead. Has troubled Anna, indeed, witnessed a gruesome scene of blood-stained domestic violence or is her wine-addled mind playing cruel tricks on her?