Carol turns out the attic. Mike finds an old gramophone and starts work to restore it. The girls get a laugh out of a photograph of Carol's great-grandmother wearing an old-fashioned bathing suit. They find it even more funny when they hear she was arrested for indecent exposure because she was showing her knees. Then Cindy finds another photograph which looks like Jan, and Carol says it is Aunt Jenny as a girl. Jan is awed at the resemblance and wants to know what Aunt Jenny looks like now. She writes Aunt Jenny in order to exchange photographs.
When the photograph arrives, Jan is appalled at what Aunt Jenny looks like now. She gets worried that she will end up the same way and starts imagining things about getting wrinkly and ugly. The others are baffled about her conduct. Marcia goes to speak to Jan, and Jan explains the problem and shows her the photograph. Marcia tries to talk sense into Jan, but Jan is inconsolable.
Carol gets a telegram from Aunt Jenny to say she will arrive the next day to meet Jan. When Carol tells Jan, Jan is appalled. She explains the problem to her parents and does not listen when they try to reason with her. Meanwhile, Mike is making some progress on the gramophone, but it still needs work.
Aunt Jenny arrives, all eager to meet Jan and the other kids. She has a colorful, irrepressible personality that any kid would like, and she is a rich woman who travels the world and knows all sorts of celebrities. The other kids take an instant shine to Aunt Jenny and the gifts she has for them, but Jan is nowhere around. When Carol brings Jan down, Aunt Jenny is very pleased to meet her soul sister, but Jan is unenthusiastic. It gets worse when Aunt Jenny gives a caricature of herself to Jan. Eventually, Carol and Mike are forced to explain the problem to Aunt Jenny.
Aunt Jenny tells Jan that she does not like her appearance all that much either, but chooses it over plastic surgery because there are too many plastic surgery beauties while her own appearance is more unique. (Later, Jan hears that Aunt Jenny turns down wedding proposals because she considers herself too young to settle down - and she is 40 years older than Jan!) This breaks the ice between them. Jan gets to like Aunt Jenny even more when she discovers what a real character her aunt is, such as winning a llama as a reward for a fund-raising campaign. The kids are delighted when Aunt Jenny throws a suriyaki party and slurping is allowed because it is considered polite and shows them how to eat rice. Jan is fascinated by all the stories Aunt Jenny has to tell about her travels, and the wedding proposals that she gets.
But then Aunt Jenny's secretary phones (the latest of several of her calls that keep interrupting things) to remind her of a dinner at the American embassy at Paris. This means Aunt Jenny has to go, much to the family's dismay. Jan wishes Aunt Jenny could stay, and Aunt Jenny is glad to hear it. She promises Jan that she will be back. Jan has definitely changed her mind and tells her parents that she now wants to look just like Aunt Jenny when she grows up.
Later, Jan receives a gift from Aunt Jenny - a leg plaster cast. Aunt Jenny had an accident from skiing in Switzerland after the dinner at the American embassy. She had her leg cast autographed and is now sending it to Jan. The parents are stunned at the signatures, which include Jean-Claude Killy, Peggy Fleming, Sir Edmund Hillary, and Paul Newman. Then Jan receives a call from her boyfriend Stevie and tells him she will not be ready to settle down until she is at least 60, but at date on Saturday night is okay.