Stanwyck plays Leona Stevenson, a spoiled, bedridden daughter of a millionaire. The telephone is her sole connection with the outside world. One day, while listening to what seems to be a crossed phone connection, she eavesdrops on two men planning a woman's murder. Leona calls the phone company and police, only to be ignored. Adding to Leona's dilemma is the fact that her husband Henry  is missing. After a number of phone calls, the terrorized Leona begins to piece together the mystery. Her uneducated husband, who works for her wealthy father, turns out to be not all he seems. Finally, to her horror, Leona realizes she is the intended victim.