Ann Bolt is driving home and encounters a sudden summer thunderstorm. She pulls up to a stylistic home to ask for directions, and the woman of the house invites her in via the intercom system. Ann goes in and discovers that the home is in a new modern style, and the woman, Pat Blessington, greets her. They exchange introductions and Pat explains that her husband David is making coffee. While they wait, Ann asks to use the phone and Pat leads her to a strange new model of videophone that Ann has never seen before. She calls home but gets a busy signal, and Pat suggests that she "program" it to dial later.
As they wait, Ann asks for a cigarette. Pat is surprised at the request, noting that most people don't smoke. She gives Ann a pack that David has on hand for guests, and Ann is pleased at the taste. Checking the package, she is surprised that she doesn't recognize the brand, and asks Pat if she can keep them. Ann immediately agrees, and Pat notes that she's surprisingly trusting, letting a stranger in. Pat explains that one of the modernistic "paintings" is actually a closed camera. David arrives and shows Ann a map device that can find her path back to her home. He programs in her address and gives her directions, and invites her to come visit again sometime. Pat insists as well and Ann agrees before leaving.
Ann drives out of the storm and arrives at her home, but is surprised to discover that the car is covered in dust and the bushes are dry. She goes inside and her husband Tony Bolt confronts her. He's wearing a hag costume and shrieking at her, and Ann insists that she's nothing like that. Tony relents but they argue that she's changed and he can't relax around her anymore. Ann apologizes for her behavior and then says that she was lost in the storm, but Tony says that there hasn't been any storm that night. When he asks why Ann didn't call, Ann insists that she did and wonders if he was cheating on her because he wasn't home when he called. Tony assures her that he'll always love her, and they go up to put their son David to bed. The maid, Yvonne, waits for them and exchanges a glance with Tony as he goes by.
Ann accepts the Blessingtons' invitation and returns to their home. Tony is fixing neighbor woman Julie's music player, which plays strange music that Ann doesn't recognize, but that Julie insists is playing everywhere. Julie gives David a kiss on the mouth and leaves, and Ann asks if they want children. David and Pat say that they're still getting used to each other, and David shows Ann a scar on his thumb that he says he got when he was slicing cake when he was four years old. When Ann notes that she's surprised Pat isn't surprised about the kiss, Tony explains that jealousy is dangerous, and it destroyed his mother when she imagined her husband with another woman. His mother killed her husband when David was four, and then killed herself before she could go to trial. A distant relative named Blessington took David in and gave her his name so no one would connect him to the scandal. As Ann goes, David warns her to beware of jealousy. He offers to show her a photo of his mother that his guardian gave him, but Ann leaves before he can.
When she returns home, Ann discovers that Tony isn't home for their son's birthday. She calls him and he says that he went out with a cousin, Jane, who is visiting from out of town. They start to argue, but David cries from the next room. Ann runs in and Yvonne explains that the boy cut his thumb while slicing his fourth birthday cake. When Tony comes home, Ann confronts him, noting that she has never heard of his cousin Jane. Tony explains that the woman is a distant cousin, Jane Blessington. Upon hearing the last name, a shocked Ann goes to bed. Jane comes to visit her, and Ann asks her to take care of David and show him a photo of Ann when he grows up. Tony comes in and Ann explains that somehow she traveled 20 years into the future to see their son, David, as a grownup. Tony tries to find David Blessington in the phone book without success, and Ann explains that the future David knew who she was, and tried to warn her against killing Tony. Tony insists that Ann wouldn't kill anyone, but she isn't convinced.
That night, Ann tries to find proof of her trip through time and remembers the pack of cigarettes. They have a date of manufacture of June 7, 1989, and she takes them to show Tony. She finds him and Yvonne kissing in kitchen, quietly retreats, and gets Tony's gun from the desk. She then returns and shoots him dead.
Later, Jane comes to see Ann in prison. Ann has accepted her fate and says that she won't need a lawyer because she'll kill herself first. She explains to Jane that she knows that David will grow up happy, and that he forgives her because he kept the photo that Ann has given to Jane to give to him.