The third season of One Tree Hill, an American teen drama television series, began airing on October 5, 2005.

[1] The first semester of senior year has begun for the major protagonists, and it will be unforgettable as Tree Hill and its residents undergo significant changes and hardships.

Though she is unaware of her limited time, Peyton accepts Ellie as her birth mother and makes an effort to build a relationship with her.

While Lucas struggles with his heart condition as the basketball season heats up again, Karen receives news from an old acquaintance who is returning to town that could impact her life forever.

In another scene, Dan takes up a new political role in the community and starts a thorough investigation into the person who attempted to kill him.

Dan might lose against a new redhead girl who moves to Tree Hill as the town's worst inhabitant.

Peyton feels her mother lied to her by not telling her she was adopted: Larry reassures her they planned to, but couldn't because Mom died, then he was scared to upset her.

Dan announces he's running for Mayor to Deb, telling her he will give her the divorce if she stands by him throughout the campaign.

Dan announces his run for Mayor at the Midnight Madness basketball game, when they retire his jersey.

Lucas grows tired of Nathan ignoring Haley leading them to have a fight on the court: furious, Whitey makes them co-captains of the team.

Brooke has a fight with a new cheerleader, Rachel Gatina, who is trying to steal her spotlight; she's also the girl whom Lucas met at the party.

Karen does a radio interview for the election, but Dan ambushes it by calling her and asking unflattering questions.

Peyton gives Haley a ride to the game and tells her she is sick of everyone leaving and that is the reason she has been mad at her: the two finally make amends.

Brooke, Haley and Mouth successfully launch the Clothes Over Bros' website, only to find that demand far exceeds supply.

The Ravens lose their second game in a row, which leads Whitey to make the boys clean up a dilapidated old court.

Brooke receives a mysterious letter inviting her to a fashion showcasein New York - later she sees it is the same weekend as a big game/ cheerleading date.

Keith is questioned by police for the fire, but cannot be held as they have no evidence, then he asks Karen out on their first date to the Ravens game.

Lucas and Brooke begin arguing due to a letter he signed off using the exact words he had used the year before in one for Peyton.

Peyton talks about how she loved Lucas but let him go and now she realized it was a big mistake: Ellie tells her it is never too late.

Clips of the students' time capsule from Junior year are leaked and played on TVs all over school.

During the charity night (for breast cancer research) to launch the CD, Peyton flirts with Fall Out Boy songwriter Pete Wentz at Tric.

The show references Jack's Mannequin singer, Andrew McMahon, and his real life battle with leukemia.

Jimmy Edwards, a bullied student at Tree Hill High, who used to be friends with Lucas and Skills, is depressed after the leaking of the time capsule.

The school is put in lockdown while Jimmy takes Haley and other students hostage in the tutor centre.

Brooke discovers something about Rachel's past, while Peyton makes out with Pete Wentz, after he turned up and made everyone breakfast.

Seeing how Keith's death has been for Karen and realising he has been putting his life at risk, Lucas decides to tell her, Whitey and Nathan the truth about his heart condition, then quits the team because continuing to play is too dangerous.

Nathan and Haley begin organizing their wedding, while Brooke uses what she's discovered at the cabin to take revenge on Rachel (she used to be a fat child).

Instead of using a plane ticket Pete has left for her, she goes to Savannah to find Jake, thinking it could be what her heart wants.

Peyton is spending some time in Savannah with Jake and the two rekindle their relationship: feeling happy with him and Jenny and seeing a good art college in town, she asks to stay and proposes to him.

At the wedding, Lucas, thinking she already knew, lets it slip with Brooke about the kiss with Peyton, leading to yet another fight between them.