According to five-year-old Sophia, marriage is all about choosing who you want to play with, so when her father tells her she can't marry him she's devastated. Later, Sophie's father gives her a journal with a lock for her to write letters in to her future husband. He explains that doing so will help her discover who she'll want to marry. As she grows up, the letters focus on Hanno, her brother's friend. At nineteen, Sophie runs into Hanno in Florence, Italy. He insists on showing her the city, and as the day goes by, she falls for him again. Realization that Hanno is a cad doesn't hit her until Hanno's roommate, Peter Stark, walks in, sees them kissing, and asks if he should find another place to sleep. Ten years later while home for Christmas, she seesPeter at Hanno's wedding. She learns that Peter has joined the church, but remains convinced she will marry her boyfriend, Griffin. Sophie's boss contacts her during Christmas, informing her that she has been chosen to create an ad for Luxe Air, a new luxury airliner. Later, when she realizes Griffin is a dufus and that Peter is staying a few days with her brother and his family in London, she flies there, deciding to work on the ad and pursue him at the same time. Peter helps on ad assignment. They workwell together and finish in time. Sophia realizes she loves Peter and proposes. He says he can't. She goes to bed devastated and has one last dream with Sarah, her future daughter, who tells her she has to leave. In the morning, she hears her brother andhis wife are scurrying around, but she doesn't think anything of it, until she walks out and sees Peter, wearing a tux, ready to propose to her.