Elizabeth decides that it would be really cool to take part in a foreign exchange student program, so she sends off for more information. When the packet comes, she learns that they can't take part in it because they don't speak a second language. Enter Ned and Alice, who decide that taking in a foreign exchange student is a great idea.
Jessica immediately starts daydreaming about seeing a hot guy show up. When the lady from the program calls, she mishears Giovanna as Giovanni and assumes she's a boy. She tells all the Unicorns, and they start planning a bunch of parties and events to welcome him to town. Amy and Elizabeth have to break the news that it's actually a girl staying with them.
While trying to track down a cot for her, they meet a neighbor named Mrs. Dalone. Her family was from Italy, so she introduces them to spumoni and shows them photos her cousin took. Jessica instantly thinks that Giovanna will be a country bumpkin with no fashion sense and no idea about life in the city city. Elizabeth tries to make her realize that she comes from a big city, but Jessica won't listen.
Cut to Giovanna getting off the plane in a leather jacket Jessica once saw in a magazine and loved. She can barely speak English on the first night, but she has a better handle on it the next day and blames it on her lack of sleep. She quickly lets them know that she's far better than them. Giovanna has her own scooter, drinks coffee at breakfast, has wine with dinner, and even has her own maid. She also looks down on their strawberries for not being fresh and wrinkles her nose at the idea of pancakes.
When it comes time to introduce her to the kids at school, things get even worse. Even though he's Lila's boyfriend, Rick falls all over himself to be around her. All the guys in school go all out to get her attention, including Bruce and Aaron, Jessica's boyfriend. The Unicorns are less than happy and demand that she do something about it.
Jessica is supposed to move Giovanna into her room halfway through her visit, but she keeps making up excuses. The twins take her to see Mrs. Dalone, and she acts like a huge bitch. She complains about her accent, the way she speaks Italian, and even the cakes that she made for their visit. Once Jessica also sees her sharing ice cream with Aaron, she decides to make her pay.
The twins planned a pool party for Giovanna, and everyone in school shows up. Janet, Lila, and Ellen are the last to arrive. Lila shows up in a red bikini, which was supposedly a one of a kind, but it's the same suit that Giovanna has. Every guy flocks around her and ignores everyone else.
Giovanna has to write an essay comparing America and Italy and read it in class. Lila and Jessica offer to "help" her with her English, but Lila actually changes the entire essay to talk about how cool America is without mentioning anything about Italy. She gives it to her at the last minute, and when Giovanna tries to stop reading it, the teacher makes her go on.
When they get back that night, she tells them that she called the head of the program and made arrangements to leave the next day. The twins finally tell her how her actions affected everyone around her. Giovanna claims that she never knew people were upset with her. She says that she doesn't really know all the right words and sometimes says the wrong thing and that she never meant to hurt anyone.
They go back to see Mrs. Dalone so Giovanna can apologize. She announces that she planned her own trip to Italy, and the two make plans to get together. The book ends with Giovanna on her last day in Sweet Valley. Suddenly, she's best buddies with both twins and teams up with Jessica to tease Elizabeth about being so good in school.
The B-plot deals with Mr. Seigel and Mrs. Wyler sneaking around school. They keep whispering in the halls and spending a lot of time together. The Unicorns try to figure out what's going on, and Giovanna tells them that it's clear they are secretly in love and planning a wedding. They buy them a gift and make a big speech in school, but they aren't getting married. They're just working on a new science class.
*The Wakefields plan to turn the den into a bedroom when they think they have a male student, but when they learn their student is a girl, they decide to have her sleep with the twins. Why can't she still have her own room?
*Check out that cover! Most of these bathing suits are nowhere near appropriate for sixth grade girls.
*Then again, Giovanna wears full makeup, leather pants, and a pair of leather boots to middle school.
*Giovanna really is a little bitch. She turns up her nose at everything, treats everyone pretty rudely, and then acts surprised that people don't like her.
*She also flirts with every guy who crosses her path, and then can't believe that people thought she was flirting or trying to steal their guys.
*The Unicorns present is a silver picture frame that costs $39.99, which is probably the most affordable thing ever mentioned in one of these books.