After playing with a Ouija board with her brother Larry (Fisher Stevens), eleven-year-old Faith Corvatch (Marisa Tomei) becomes convinced that her soulmate, the man she is destined to be with, is named "Damon Bradley." This belief is strengthened when a few years later a carnival fortune teller tells her that "Damon Bradley" is the name of the man she will marry.
Fourteen years later, Faith is a teacher at a Catholic school and is engaged to a podiatrist. Ten days before their wedding, Faith learns that her fiancé's high-school classmate Damon Bradley will fly to Venice, Italy that day. Determined to meet him, Faith follows his trail with her sister-in-law Kate (Bonnie Hunt) from New York City through Venice and the Italian countryside to a streetside restaurant in Rome, but they never quite catch up with him.
Faith meets a young American man (Robert Downey Jr.), but has no interest until he identifies himself as Damon Bradley. They spend a romantic evening together and fall hopelessly in love. Then he reveals that his actual name is Peter Wright, so she angrily leaves him and prepares to fly back home. Meanwhile, a suave Italian businessman named Giovanni (Joaquim de Almeida) has been wooing Kate.
The next morning, Peter tells Faith that he searched for Damon overnight and discovered that he has moved on to Positano. Giovanni agrees to drive the three Americans there. At a posh hotel, Faith meets Damon, a good-looking playboy, and invites him to dinner. Peter spies on them at the restaurant until Damon makes unwelcome sexual advances with Faith. It turns out that this "Damon" is really a friend of Peter's who has helped Peter stage the entire scene.
Back in the United States, Larry finds out that his wife Kate is in Italy. He travels there to find her while Kate and Faith are again planning to return home. Larry arrives in time to make up with Kate. He also reveals to her that Faith's childhood "Damon Bradley" phenomenon was a prank: Larry intentionally spelt out the name on the Ouija board, then he paid the fortune teller to tell Faith that her true love had the same name. He hasn't told Faith the truth because he has been afraid she would never speak to him again.
Faith and Peter are at the airport when they hear Damon Bradley paged. At the information desk, they finally meet Damon, who is not especially handsome. Peter explains to Damon why Faith has been following him. He also tells Damon that he (Peter) is in love with her, then boards his flight home to Boston. Damon asks Faith if she loves Peter. She realizes that she does and rushes to join Peter on his plane. The airport staff delays the flight until Faith can board. She and Peter embrace and kiss as the passengers and crew applaud. Their plane then flies into the sunset.