Sorry, Wrong Number (1948)

Leona Stevenson is an alluring, wealthy, irritating hypochondriac whose psychosomatic illness has her bedridden. Leona's only lifeline is the telephone, which she uses to excess. One evening, Leona impatiently tries to locate her henpecked husband Henry who is late coming home. However, when phone lines cross, she overhears two thugs plotting a murder. Desperate to thwart the crime, Leona begins a series of calls--to the operator, to the police, and others--and eventually deduces the shocking identity of the victim. Meanwhile, Henry is having his own problems; he's become involved in a swindle and is being blackmailed. The film follows Leona, trapped in her lush apartment, as she tries to prevent an innocent person from being murdered.