During the summer of 1999, a group of teenagers, through interconnected narratives, live through their last day of high school and prepare for the future. Holly, once the new girl in school, does whatever it takes to remain popular. Dawn, who is secretly a lesbian, battles drugs. Tori is the valedictorian of her class, but, on the eve of graduation, she decides to experiment with drugs for the first time.

In Tree Hill, North Carolina two half brothers share a last name and nothing else. Brooding, blue-collar Lucas is a talented street-side basketball player, but his skills are appreciated only by his friends at the river court. Popular, affluent Nathan basks in the hero-worship of the town, as the star of his high school team. And both boys are the son of former college ball player Dan Scott whose long ago choice to abandon Lucas and his mother Karen, will haunt him long into his life with wife Deb and their son Nathan.