Episode: 4×21 (Season 4 Episode 21)
Name: All of a Sudden I Miss Everyone
Originally Aired: Jun. 13, 2007
Plot: In the fourth-season closer, Rachel returns to town to throw a graduation party for the Tree Hill High senior class. There, the teens say goodbye to each other as they each embark on their post-high school plans. Nathan and Haley adjust to life as parents while Lucas and Peyton prepare to part for the summer. Meanwhile, while recovering in the hospital, Karen has a dream about Keith and their daughter; Dan’s grief and confession lead him to consider deadly action; and Karen confronts Dan about Keith’s murder.