The story is fairly simple. Bad Boy Landon Carter gets caught after pulling a prank on another kid and to avoid further problems he gets roped into helping in the school musical opposite Jamie Sullivan, the reverend's daughter and owner of exactly one sweater.
At first, he doesn't want anything to do with Jamie, as she doesn't fit in with his life or his friends, but through getting to know her, he falls deeply in love with her, and is ready to do just about anything to make her family.
Of course, this being a Nicholas Sparks book, things take a turn for the tragic when Jamie confesses that she has leukemia. In the book, the ending is more ambiguous, but in the movie is pretty clear that Jamie dies and I confess to crying or at least getting teary eyed each time.
Plus, I love both Mandy Moore and Shane West and I buy them together.