"Things I Forgot At Birth" is the second episode of the fourth season of One Tree Hill and the 69th produced episode of the series. It was broadcasted on October 4, 2006. As Nathan, Rachel and Cooper's lives remain precarious following the car accident, Brooke celebrates her 18th birthday but finds it diminished by her struggles with Peyton. Lucas and Karen come to terms with her pregnancy and with the pregnancy of someone close to Lucas, while Deb's past addictions intersect with Haley in an explosive manner.