Rosie and Alex have been best friends since childhood. On Rosie's 18th birthday, they kiss while drunk but don't remember it. Years later, Rosie gets pregnant after a one-night stand with Greg. She doesn't tell Alex about the pregnancy when he leaves for college. After various relationships and misunderstandings, Rosie discovers a letter from Alex expressing his feelings for her just after he marries Bethany. Rosie objects at the wedding but is too late. In the end, Alex realizes Bethany isn't right for him and that his true love has always been Rosie.