Mrs. Stevenson is a housewife in 1940s New York City whose unspecified health condition confines her to her bed. The telephone serves as her only connection to the outside world. Described as querulous and self-centered, her entitlement surfaces as she grows frustrated with telephone operators and police officers while trying to report a murder plot she overhears on a crossed wire.

Elbert is Mrs. Stevenson's husband, an attentive partner who has scarcely left her side since she became ill twelve years ago. His sudden inability to be reached by phone and an unexpected business trip to Boston leave his wife alone in their apartment, triggering her intense anxiety.

The 1st Man is a calm, collected individual coordinating the planned murder of an unnamed woman. He provides explicit instructions over the phone, detailing the timing of the private patrolman's breaks and the passing subway train to ensure the crime goes unnoticed.

George is the man assigned to break into a woman's home and carry out a stabbing at 11:15 PM. He listens to the operational details over the phone, including instructions to make the crime look like a robbery and ensure the victim does not suffer long.

Sergeant Duffy is a New York City police officer who fields Mrs. Stevenson's emergency call. Preoccupied with his meal and restricted by police protocol, he is kind but dismissive of her vague report, viewing her demands for a city-wide search as an overreaction.

A telephone company employee who responds to callers with automated, unemotional phrases. She attempts to follow standard procedures regarding wrong numbers, maintaining a procedural distance despite the frantic nature of the request.

A telephone supervisor handling an escalated situation. She calmly explains the technical impossibility of tracing a disconnected call and advises that reporting a potential crime is a matter for law enforcement, not the telephone company.

Eloise is the maid working in the Stevenson household. Because of her employer's health condition and physical restrictions, she is one of the only people who interacts with her in person on a regular basis.

A receptionist working the desk at Henchley Hospital. She explains the hospital's shortage of registered nurses due to the war and refuses to dispatch medical staff without official papers from a doctor.