All of a Sudden I Miss Everyone

S4 E21: The Tree Hill High School graduates share their bittersweet final moments together. At the same time, both Karen and Haley go into labour, while their loved ones stand by. Brooke has a surprising reunion with someone from her past, Peyton struggles with the thought of spending the summer away from her friends, while Dan tries to assuage his guilt by making a life-changing decision.