One day, while typing lines of a manuscript during a rainstorm, aspiring writer Vida Dove cries, recalling the events of the past few weeks: Thirty-year-old Vida, who lives with her paraplegic brother-in-law, Murray Myer, her younger sister Evelyn, and their two young children, David and Shirley, gets into an argument with Murray about her stalled romance with fiancé Eddie Collins. Embittered by his condition, former dancer Murray calls Vida a sex-starved spinster, then tries to goad her into saying that he is not “man enough” for Evelyn. Vida, who once dated Murray, refuses to respond to his taunts and leaves for the Circle Inn, a diner owned by Murray, but maintained by Vida and Evelyn. Soon after Vida relieves Evelyn at the counter, Eddie shows up with Glenn Harris, an old Army buddy who owns a nearby gas station. Smitten by the handsome Glenn, Vida happily entertains him after Eddie, a public utilities worker, is called out on an emergency. Over coffee, Vida tells Glenn about her writing and her relationship with Murray, who was paralyzed in a car accident. His work done, Eddie returns to the diner to escort Vida home and annoys her with his adolescent joking. At home, Murray tells Eddie and Vida about recent medical studies that tout sea bathing as a cure for paralysis and reveals his desire to sell the diner and move to the seashore. When Vida balks, questioning how they will live without income from the diner, Murray insults her repeatedly and becomes so agitated that he tips over in his wheelchair. While Evelyn and Eddie rush to Murray’s side, Vida retreats to the bedroom she shares with David and Shirley and daydreams about Glenn. Later, at the diner, Vida tells Evelyn about Glenn, comparing him to a panther. To Vida’s delight, Glenn returns to the diner to invite Eddie and her for drinks that evening. Soon after arriving at Glenn’s half-furnished house, Eddie receives another emergency call and leaves Vida with Glenn. Glenn and Vida flirt while discussing decorating ideas, and Glenn leads her into his bedroom and kisses her. Suddenly panicked, Vida runs off without explanation, but at the diner the next day, apologizes to Glenn for leaving so abruptly. Although Glenn reassures her, he lights up when pretty, friendly Evelyn walks in. Sensing Glenn’s attraction for her sister, Vida offers to stay during Evelyn’s shift, but Evelyn reminds her that David and Shirley need to be picked up. That night, Murray becomes upset when Evelyn returns home late, and Evelyn and Vida must give him an injection to prevent life-threatening convulsions. After getting Evelyn to admit privately that she was with Glenn, Vida weeps in her room, cursing her sister for stealing both Murray and Glenn. The following night, Evelyn again is late getting home, and despite attempts by Vida and Eddie to fool him, Murray deduces that she has been out dancing. Enraged, Murray accuses Evelyn of trying to “sign his death warrant” and reminds her that she is his only reason for living. Although guilt-ridden, Evelyn tells Vida the next morning that she and Glenn are deeply in love. Heartbroken, Vida gets Evelyn to take her shift at the diner and is surprised but overjoyed when Glenn drops by the house to ask her out. While Vida dresses for the occasion, Glenn chats with an unsuspecting Murray, who talks lovingly of Evelyn and his hopes for a complete recovery. On their way to a popular night spot, Vida gushes that she has been waiting for this moment for a long time and is oblivious to Glenn’s distracted mood. In the middle of a dance, Glenn suddenly pulls Vida outside and asks her to cover for Evelyn, whom he wants to take the beach. Although devastated, Vida agrees and, at the diner, hides her anger when Evelyn admits that it was her idea to ask Vida to help. Vida is unable to work, however, and walks the streets, haunted by romantic images of Glenn and Evelyn at the beach. When Vida arrives home in her diner uniform, Murray questions her and gets her to admit that Glenn is with Evelyn. Murray moans with self-pity and longing, and near hysterics, Vida screams that, even when they were children, she was expected to make sacrifices for her pampered sister. With Murray’s sarcastic rebukes ringing in her ears, Vida retreats to the bathroom and is unmoved when she hears him lapsing into convulsions. Vida downs some sleeping pills and the next morning, discovers that Murray is dead. While comforting the shocked Evelyn, who arrived home in time to give Murray an injection, Vida learns that her sister is suspected of murder, as the police have determined that the syringe was filled with poison. Later, at the police station, Vida is questioned about her sister’s affair and the fact that the medicine bottle was also found to contain poison. Unaware that Vida always filled the syringe for Evelyn and that Vida had brought home some cockroach poison from the diner, the police accept Vida’s explanation that her sister committed the crime under extreme emotional duress. Outside the station, Vida tells Eddie that their engagement is off, then goes to see Glenn at his gas station. There, Glenn rails against her, accusing her of betraying Evelyn. Glenn vows to prove Evelyn’s innocence and reveals that, at the beach, he and Evelyn had agreed to end their affair and that she therefore had no motive for murder. After Glenn states that he never cared for her, Vida, stunned, walks back to the police station in the rain, resolved to “finish the story she started a long time ago.”