When Landon has some trouble learning his lines, he asks Jamie for help. She agrees to help him if he promises not to fall in love with her. Landon laughs off the strange remark, believing Jamie to be the last person with whom he would ever fall in love. After all, Landon has access to the prettiest and most popular girls in town; and between her shy demeanor and old-fashioned wardrobe, Jamie doesn't exactly fall into that category.
Landon and Jamie begin practicing together at her house after school. The two form a tentative friendship, and Landon learns that Jamie has a wish list of all the things she hopes to do in her life, such as getting a tattoo and being in two places at once. One day, Jamie approaches Landon at his locker, where he is hanging out with some of his friends. When Jamie asks Landon if they are still on for practice tha
t afternoon he smirks, "In your dreams." His friends laugh and Landon's smirk falters as Jamie's face fills with betrayal and embarrassment. That afternoon Landon arrives at Jamie's house, hoping that Jamie will still agree to help him. But she refuses to open the door. When she eventually does, she sarcastically remarks that they can be "secret friends." She slams the door in his face when he agrees. Landon eventually learns the script by himself.
During the play, Jamie astounds Landon and the entire audience with her beauty and voice. Landon kisses Jamie during the play, which was not in the script, and Landon tries to get close to Jamie, but she repeatedly rejects him. It is only after a malicious joke played on Jamie by Landon's friends that Jamie agrees to get to know Landon after he punches out Dean and shuns Belinda (his friends who played the joke) and takes Jamie home. The two pursue a relationship. He asks if she will go to dinner with him, but she replies that she is not allowed to date. He wants the date so badly that he goes to her father in the church and asks him if he can take Jamie out to dinner. Her father says no. Landon asks for her father to give faith in him. He eventually says yes. He takes her out to dinner and dances with her, something he never did for anyone else. Landon then sets out to help her accomplish a few things on the list. One memorable date had Landon taking Jamie to the state line. He excitedly positions her on the line in just the right way, and when Jamie asks him what he's doing he tells her "You're in two places at once." Her face lights up with joy, as she realizes that Landon set out to make her impossible dreams come true. One evening, Landon asks her to find a star for him with her telescope. When she asks why he is looking for it, he replies, "I had it named for you." She embraces him and whispers "I love you" to him for the first time.
Jamie finally tells Landon that she has terminal leukemia and has stopped responding to treatments. Landon gets upset at first. Jamie tells him the reason why she didn't tell him because she was moving on with her life and using the time she had left but then Landon happened and she fell in love with him. Jamie starts to break down as she says to Landon "I do not need a reason to be angry with God," and she flees.
Landon goes to his doctor father's house and asks him to help Jamie. His father hesitates a bit and says that he needs to examine Jamie and know her medical history before he could do anything. Landon responds by leaving in a huff.
Landon and Jamie make up the next day, by hugging and he tells her that he will be there for her always. Soon, word gets out about Jamie's illness. Eric, Landon's best friend comes and tells him how sorry he is and that he didn't understand. Later, Dean and Belinda both come and apologize.
Jamie's cancer gets worse and she collapses in her father's arms. He rushes her to the hospital where he meets Landon. Landon doesn't leave Jamie's side until her father practically has to pry him away. Jamie's father sits with Jamie and tells her that "If I've kept you too close, it's because I wanted to keep you longer." Jamie tells her father that she loves him so much and he eventually breaks down into tears.
The next day, Landon comes to the hospital and sees Jamie being wheeled out of the ward. He asks Jamie what's going on and she replies by asking him to thank his father for the help. Landon asks Jamie's father what she means. He tells him that his father is going to pay for private homecare for Jamie. Landon is stunned, so later in that night, he knocks on his father's front door. His father answers. Landon whispers "thank you" and his father hugs him. With all the exhaustion and fear billowing over, Landon breaks down in tears in his dad's arms.
Landon continues to fulfill various wishes on Jamie's list, such as building her a telescope so she can see a comet. Her father who at first didn't approve of him helps out. After Jamie sees the comet through the telescope, Landon proposes marriage with Jamie accepting. Through this process, Landon and Jamie learn more about the nature of love. The movie ends with Jamie's death, but only after the couple are married in the same chapel as was Jamie's deceased mother, the event that topped Jamie's wish list. Landon himself becomes a better person through Jamie's memory, achieving the goals that he set out to do, like she did.
Four years later, Landon visits Jamie's father. It is obvious that Jamie helped him to focus and become a better person. For example, he reveals he has finished college and been accepted into medical school; prior to meeting her he had no plans for life after high school. He tells Jamie's father that he is sorry he could not grant Jamie's wish to witness "a miracle" before she died. Her father replies by saying, "She did. It was you."
While there are many similarities to the novel by Nicholas Sparks, many changes were made. On his personal website, Sparks explains the decisions behind the differences. For example, he and the producer decided to update the setting from the 1950s to the 1990s, worrying that a movie set in the 50s would fail to draw teens. "To interest them," he writes, "we had to make the story more contemporary." To make the update believable, Landon's pranks and behavior are worse than they are in the novel; as Sparks notes, "the things that teen boys did in the 1950s to be considered a little 'rough' are different than what teen boys in the 1990s do to be considered 'rough.'"
Sparks and the producer also changed the play in which Landon and Jamie appear. In the novel, Hegbert wrote a Christmas play that illustrated how he once struggled as a father. However, due to time constraints, the sub-plot showing how he overcame his struggles could not be included in the movie. Sparks was concerned that "people who hadn't read the book would question whether Hegbert was a good father", adding that "because he is a good father and we didn't want that question to linger, we changed the play."
A significant difference is that at the end of the novel, unlike the movie, it is ambiguous whether Jamie died even though during the 1950s cancer meant death. Sparks says that he had written the book knowing she would die, yet had "grown to love Jamie Sullivan", and so opted for "the solution that best described the exact feeling I had with regard to my sister at that point: namely, that I hoped she would live." In the novel, Landon's father is a congressman, but in the film he is a cardiologist who helps Jamie with her illness. Due to his career, he had enough money to pay Jamie's home medical attention.
Smaller differences also exist, such as when Jamie gives Landon her mother's book in the movie, she says "Don't worry, it's not a Bible". In the novel Jamie does give him her mother's Bible with her favorite passages underlined. In the novel Landon joins the school play after he is asked by Jamie to do so; in the movie he is forced to be in the school play.