It’s always rush hour at Chicago’s County General. Every day . . . every moment . . . brings new challenges, new triumphs, and new losses. But no one ever expected that one of those losses would include one of the ER’s talented med students. The pulse-pounding rotation continues with all 22 episodes of ER’s sixth sensational season. New storylines and new complications unfold as young doctors (Goran Visnjic, Michael Michele, Ming-Na, and others) face the day-in, day-out rigors of the life-and-death decisions of their trade. Meanwhile, a veteran physician (guest star Alan Alda) confronts the bittersweet conclusion to his career. In addition, old stories resolve: as Jeanie Boulet finds love and family, Carol Hathaway (Julianna Margulies) gives birth to twins and makes a long-awaited decision that fans have been clamoring for. And tragedy strikes — swiftly, irrevocably, and for its survivor, Dr. John Carter (Noah Wyle), perhaps irreparably.