In the season finale, George (portrayed by T.R. Knight) is critically injured when a bus jumps a curb and hits him, as he is in the process of saving the life of a woman. Despite the efforts of his colleagues and friends, George's injuries are too severe and he succumbs to his injuries.
The season also sees several major life-altering events for the other main characters. Meredith (Ellen Pompeo) learns that she is pregnant with Derek's (Patrick Dempsey) baby. Cristina (Sandra Oh) and Owen (Kevin McKidd) get married. Izzie (Katherine Heigl) continues to struggle with her cancer and decides to leave the hospital and start a new life.
Finally, Alex (Justin Chambers) begins a new chapter in his life as a pediatric surgical resident.