With the fates of Izzie Stevens (Katherine Heigl) and George O’Malley (T.R. Knight) hanging in the balance as the series' fifth year came to a close, the new season brings more drama into the lives of the young doctors at Seattle Grace Hospital. Returning for another round of hope and heartbreak are Ellen Pompeo as Meredith Grey, Golden Globe winner Sandra Oh as the ambitious Cristina Yang and, of course, Patrick Dempsey as Dr. "McDreamy."