Lizzie McGuire prepares for her
junior-high graduation with one of her two closest friends, David "Gordo" Gordon. Their other best friend, Miranda Sanchez, has chosen to skip the graduation ceremony in favor of a trip to
Mexico City to visit her relatives. During the ceremony, Lizzie trips onstage and accidentally brings the curtain down on her fellow graduates; this causes her to be teased by her younger brother Matt and her former best friend Kate Sanders. After graduation, Lizzie and her classmates embark on a trip to
Rome, chaperoned by their strict future high school principal, Angela Ungermeyer. The rest of the class chose a trip to a water park instead. To their dismay, Lizzie and Kate are assigned to the same hotel room. While visiting the
Trevi Fountain, Lizzie is approached by an Italian pop star named Paolo Valisari, who notices that she bears a striking resemblance to his singing partner, Isabella Parigi. He asks Lizzie to meet him at the fountain the next day, and she feigns illness to sneak away. Paolo explains that he and Isabella are booked for the International Music Video Awards, but she left Italy after their partnership breakup. He tells Lizzie that Isabella lip syncs and begs her to pose as her for the ceremony so that they won't be fined for canceling. Lizzie reluctantly agrees but soon begins to enjoy the experience and falls for Paolo. Lizzie continues to fake being ill to prepare for the ceremony, but Kate quickly figures out her secret. To Lizzie's surprise, she agrees to help her and they become friendly again. Meanwhile, Ms. Ungermeyer grows suspicious, leading Gordo to take the blame and resulting in him being sent back home as punishment. Lizzie is shocked when she learns from Kate that Gordo sacrificed himself to protect her. Back home, Matt finds Italian gossip sites with pictures of Lizzie as Isabella. He initially tells his parents he misses Lizzie, convincing his parents to fly them to Rome, during which his parents find out about Lizzie's exploits. At the airport, Gordo meets the real Isabella, who is upset that someone has been impersonating her. They realize that Paolo is planning to have a nervous Lizzie unknowingly sing live at the ceremony, as Isabella actually does, creating the impression that Isabella is a fake, which would damage the latter's career and embarrass Lizzie. Gordo and Isabella rush to the awards to stop him and warn Lizzie. When the McGuires arrive in Rome, Ms. Ungermeyer learns that Lizzie is missing. Gordo's roommate Ethan Craft reveals that she is performing at the International Music Video Awards, and Lizzie's family and the class also rush to the ceremony. Backstage, Gordo and Isabella find Lizzie preparing for the ceremony and warn her about Paolo's scheme. She refuses to believe them at first, but Isabella convinces her otherwise. Ms. Ungermeyer gets the class and Lizzie's family into the ceremony by pushing her way through the bouncers. During the performance, Isabella and Gordo expose Paolo, who is actually the one who lip syncs, by turning on his microphone, revealing his real mediocre singing voice. Upset, he runs off stage, where his displeased manager Sergei resigns, and gets ambushed outside by paparazzi. Isabella introduces Lizzie to the crowd, and the two of them sing "What Dreams Are Made Of". When Isabella leaves the stage, Lizzie finishes the song solo, displaying a newfound confidence. Later, they all celebrate at the hotel's after party, where Ms. Ungermeyer rescinds Gordo's punishment and flirts with Sergei. Although Lizzie's dad tells her she is grounded for the rest of the summer, he says he and her mom are still proud of her. Lizzie and Gordo then sneak away from the party to go up to the roof, where they promise to never let things change between them. They kiss and then rejoin the party before they get into more trouble. As the film ends with fireworks spelling "The End", the animated Lizzie does a parody of
Tinker Bell, winking at the audience. ==Cast==