Aside from their love for hoops, Lucas and Nathan seemed to have little in common. But the two young men are bound by the fact that they share the same father. The star of the basketball team, Nathan Scott (series star JAMES LAFFERTY) was raised to inherit his father's throne amidst popularity and wealth, while his half-brother, Lucas (series star CHAD MICHAEL MURRAY), was raised in modest surroundings, the only child of a single mom. When Lucas joined the Ravens team, his transition into Nathan's world created a love triangle with Peyton Sawyer (series star HILARIE BURTON). Although she was Nathan's girlfriend at the time, Peyton felt an instant connection to Lucas. Complicating things even further, Peyton's feisty best friend, Brooke Davis (series star SOPHIA BUSH), quickly set her sights on Lucas as well. And it didn't take Nathan long to notice Lucas' best friend, Haley James (series star BETHANY JOY GALEOTTI), an intriguing girl who helped bad-boy Nathan become a kinder person.
While the teenagers, including the guys' friend Mouth McFadden (series star LEE NORRIS), struggled to find their places in the world, the adults in Tree Hill were left to deal with the residue of decisions they made years ago.
Lucas and Nathan's rivalry on and off the court even brought back old emotions for grizzled basketball coach Whitey Durham (series star BARRY CORBIN). Whitey coached Dan when he was the school's star player, and now he is coaching both of Dan's sons.
Nathan's father, Dan (series star PAUL JOHANSSON), and Lucas' mother, Karen Roe (series star MOIRA KELLY), were high school sweethearts. When Karen became pregnant during their senior year, she was devastated by Dan's decision to put his own life and career first. He went off to college on a basketball scholarship, leaving Karen behind to raise their son, Lucas, alone. After Dan's dream of a basketball career didn't work out, he returned to town with Deb (series star BARBARA ALYN WOODS), the wife he had met in college, and his newborn son, Nathan.