Anthony Edwards, Noah Wyle, Laura Innes, Eriq La Salle, Alex Kingston, Paul McCrane, Goran Visnjic, Maura Tierney, Ming-Na, Sherry Stringfield

La gioia dei medici per il ritorno della dottoressa Susan Lewis viene presto stroncata dalla morte di Green. Intanto Abby e Luka non riescono ad andare d'accordo e dopo un po' si lasciano, questo permette a Carter di riavvicinarsi ad Abby ma non riesce a dirle quello che prova.
Romano invece svela a tutto il pronto soccorso il segreto della Weawer e, da questo momento la dottoressa, che non è mai stata simpatica al personale, subisce le chiacchiere dello staff.

Forse la più bella stagione in assoluto. La morte del dott. Green lascia un vuoto incolmabile nella serie e negli spettatori.

THE LETTER:

"Dear ER Gang,
so here I am, out on the beach at 5:30 in the evening. Elizabeth is sitting with me drinking juice, but I'm all about the Mai Tais. The sun is going down, Rachel is dipping Ella's toes in the ocean as they head off on a quest for the perfect seashell. I find myself thinking, you know what would make this moment complete? Some jogger dropping to the sand short of breath so I can swoop in with a piece of bamboo to perform a nice clean intubation, fix the guy up and send him off with a good simple dispo. Which I guess is my way of saying that I miss you all and that dingy place. Lots of times I thought I should have chosen a different career or gone into private practice, something easier, less grinding, more lucrative. But since I've been gone, I realize outside what I'm doing right now - sitting on this beach with my family - staying at County all those years, doing what we do on a daily basis, was the best choice I ever made. I know what you're thinking, but trust me, it's not so hard to appreciate once it's over. As much as part of me would like to believe that the ER can't go on without me, the smarter part of me realizes that you're an incredible group of doctors and nurses who approach every day with such skill, compassion and thoroughness that when it comes to patient care, I know my absence will hardly be felt. As for friendship and camaraderie, while, that's another matter. In order to leave, I had to go the way I did, but I wouldn't want any of you to think that that meant I didn't value each of you and the years we worked together, or that I didn't have things of a more personal nature to say. Most of you, I think, have an idea of what those things might be without me writing them down, but still... Ella's laughing and waving for me. Rachel's found her shell."

"Mark died this morning at 6:04 A.M. The sun was rising, his favorite time of day. I sent this on so that you might know that he was thinking of you all and that he appreciated knowing you would remember him well."