The Most Important Episodes Of 'ER', Ranked

As the second-to-last episode of Season 8, "On the Beach" offers a heart-wrenching conclusion to the life and career of Dr. Mark Greene (Anthony Edwards). The episode revolves around Greene's final days in Hawaii. Greene, faced with his own mortality, tries to repair the relationship with his daughter, Rachel. Greene opens up to Rachel, revealing a lot about himself in the process, and the two connect over simple activities like driving and surfing.

Greene's wife, Elizabeth Corday (Alex Kingston), and their youngest daughter, Ella, arrive to complete the family, although Rachel doesn't make things easy. While the episode has some carefree moments, there are constant reminders that Greene's time is limited - everything from a terrifying seizure to his daughter taking his pain pills. Greene's health deteriorates throughout the episode, and Corday urges Rachel to talk to her father before it's too late. They do talk and reminisce about her childhood, after which Greene falls asleep and never wakes up.

"On the Beach" is the end of an era. It's the final episode for Greene, although he does appear in some flashbacks. It's also a reminder of what ultimately matters. Greene's final days aren't spent at the hospital; they are focused on reconnecting with the people he holds dear. His final dream even has him looking down a long hospital corridor, only to see his family at the end, on a beach and smiling. 

For an episode that takes place on Valentine's Day, "Be Still My Heart" is not very romantic. There are definite elements of love - especially when Dr. Robert Romano (Paul McCrane) calls in Dr. Elizabeth Corday (Alex Kinston) to help him operate on his beloved dog. However, the storyline involving medical student Lucy Knight (Kellie Martin) is shocking. Knight and her mentor, John Carter (Noah Wyle), try to solve the mystery of a mentally ill patient's headaches. The patient, Paul Sobriki (David Krumholtz), turns aggressive, harming both Knight and Carter as Valentine's Day celebrations take place all around them.

The haunting image of a seriously hurt Carter falling to the floor only to see Knight bleeding, too, sets up one of the show's most compelling cliffhangers. The next episode, "All in the Family," finds the ER staff trying to save both Knight and Carter in inspired fashion. Only one of the victims, Carter, survives, and County General again struggles with the loss of one of its own.

The two-hour pilot episode of ER, "24 Hours," introduces viewers to the doctors, nurses, and other medical professionals who will become a part of their lives. The episode opens with a sleeping Dr. Mark Greene, played by Anthony Edwards, who awakens to take care of his drunken colleague, Dr. Doug Ross (George Clooney). Ross's drinking and irresponsible ways will continue to be part of the series. 

The audience also meets medical student John Carter (Noah Wyle) and the other ER physicians: Peter Benton (Eriq La Salle), David Morgenstern (William H. Macy), and Susan Lewis (Sherry Stringfield). Nurses like Carol Hathaway (Julianna Margulies) are the backbone of the County General Hospital's ER; they weave in and out of the episode, taking care of patients amid the pervasive personal and professional chaos.

The episode holds nothing back and offers real insight into the lives of everyone who appears on screen. In the final moments, viewers experience the same visceral reaction any ER employee would feel when one of their own is wheeled in, as nurse Hathaway's attempt to end her life shocks everyone. 

"Such Sweet Sorrow" focuses on nurse Carol Hathaway (Julianna Margulies), who realizes life is too short to wait for happiness. After violating a do-not-resuscitate order on a patient, Hathaway no longer wants to live in a world of things unsaid. She doesn't know if her former flame Doug Ross is still in love with her, but she's determined to find out - and heads to Seattle to do just that.

Hathaway arrives at a dock to find Ross - yes, George Clooney came back for it - and the two kiss. Not only does the episode affirm the notion that it's possible to chase dreams, but it also builds hope that sometimes they come true. From the viewer's perspective, it also brings resolution to one of the biggest romantic roller coasters on prime-time television. 

For the final episode of ER, several former cast members returned to the show. George Clooney and Juliana Margulies reprised their roles as Doug Ross and Carol Hathaway in episode 19 of the final season, but the last episode features Noah Wyle, Eriq La Salle, and Sherry Springfield. They bring the show full circle, revisiting the characters they introduced 15 years earlier. 

In one more full-circle moment, Dr. Mark Greene's daughter, Rachel Greene (Hallee Hirsh), appears at County General as a medical student. 

All these stars returning to acknowledge their roots is a testament to ER's overall significance. The final episode and its nostalgia also serves to thank the viewers for their continuous support over the years. 

"Love's Labor Lost" pushed ER to new levels of intense storytelling. Patient Jodi O'Brien (Colleen Flynn) arrives at the ER with what Dr. Mark Greene (Anthony Edwards) identifies as a routine urinary tract infection. Mere weeks away from giving birth, O'Brien is discharged, only to return a short time later, unconscious.

O'Brien has been misdiagnosed, and an emotional struggle to save her and her unborn child unfolds. With no obstetrics physician available, Greene decides to care for O'Brien. His mistakes catch up with him, and O'Brien's previously undiagnosed eclampsia leads to a fatal C-section delivery. The desperation of the situation finds no more pure articulation than when her husband, Sean O'Brien (Bradley Whitford), cries out, "Why can't you deliver this baby?"

"Love's Labor Lost" focuses almost exclusively on one patient, O'Brien, and the camera literally circles around Greene as he tries to grasp the situation. Greene hopes to bring a successful conclusion to the medical catastrophe before him, but, in the end, Sean O'Brien is left holding his newborn child while his wife lies on a gurney.