A busy Dr. Greene goes all day in solving his patients' problems until he encounters the case of a pregnant woman suffering from complications that threaten both her life and her unborn baby's.

In the middle of a torrential rainstorm, Dr. Ross stumbles across a child trapped in a drainage pipe rapidly filling with water. Doug does everything possible to save the boy, Ben Larkin. Harper develops a bond with a young girl with separated parents.

As Carter prepares to open a new facility for the underprivileged, some old friends/colleagues gather. Rachel Greene, Mark Greene's daughter, applies for an internship at County.

Dr. Greene's final days are spent in Hawaii with Rachel, teaching her to drive and surf. When he suffers a seizure, Elizabeth is called. Mark refuses to go home. He manages to make amends with his daughter before his eventual death.

Neela and Sam are shocked when they arrive back to the airport with transplant organs only to find that their plane has left them. Dr. Carter gets a surprise visit from an old friend while waiting for his kidney transplant. Dr. Banfield bonds with an abandoned baby boy that is left at the ER.

Shep and Raul respond to a massive fire without proper equipment, risking their lives to save addicts and their children. Shep will be okay, but Raul has third-degree burns covering his body; it's only a matter of time. The ER is flooded with burn victims. Chloe returns to Chicago. Doug is stood up by his father for a basketball game.

After some staff members are caught going through a dominatrix's bag, Weaver makes them attend a sexual harassment seminar, where they learn about each other.

As Dr. Greene's brain tumor begins affecting his coordination, he becomes concerned that his fate will be similar to the terminally ill patients he treats.

Mark finds himself manning a very crowded ER on his scheduled night off, filling in while Doug is out with whiplash and Susan meets with her lawyer. He tries to juggle hunger pangs, 40+ patients in the waiting room and a never-ending stream of traumas.

The last 44 minutes of ex-con & alcoholic Charlie Metcalf's life are in the ER, as he slowly succumbs to end-stage liver failure.

The ER prepares to take in victims from a plane collision, while Neela and Pratt head out to the crash site where Neela makes heroic efforts. At the end of the day, Neela gets a surprising visit.

The ER hosts roughly a dozen pregnant women when a sprinkler bursts in the maternity ward. Carter plays tour guide for the visiting surgical intern hopefuls before going through the interview himself. Benton tries to bring a hopeless patient back from the brink of death in a marathon surgery. Jerry tries to convince the others that basketball player Scottie Pippen visisted. Doug visits his father.

Because of benzene that's been spread, the ER has to close. Weaver gets felled and Carter has to take the lead.

In the series' 150th episode, a massive train wreck mobilizes the emergency room doctors. Corday, Carter and Kovac rush to the scene. Corday falls and injures her back, bringing on contractions in only her 25th week of pregnancy. While amputating the legs of a fallen firefighter, Corday stops because of her pain.

Dr. Nate Lennox, a former professor with ALS, is brought in as the progression of his disease is chronicled through his own flashbacks as he is treated by each of the doctors at one point. As Lennox wants to give up, Abby fights to convince him to keep on fighting.

Pratt struggles to get a straight story when two abused boys come into the ER with their father. Two U.S. Army officers enter the ER.

While out for a mind-clearing run, Banfield encounters a desperate situation and finds herself trying to rescue a young girl from drowning in a nearby lake. Painful memories of her son in mortal danger and Dr. Greene's heroic attempts to save him are triggered during the experience. Meanwhile, Gates attempts to pull some strings to help out a homeless war veteran, and the interns continue to struggle in the ER.

A severe blizzard leaves the ER utterly devoid of patients, leaving the staff free to goof off. In the middle of their fun, a call comes from dispatch, informing the ER of a 40-car pile-up with dozens of casualties. The ER goes from being deserted to capacity. All surgeons are called in. Bob surprises everyone with a quick and life-saving decision. A new doctor, Angela Hicks, arrives just at the right time. Ross and Linda return from the Caribbean just as Carol makes a surprise announcement.

Ross and Greene travel to a near-deserted stretch of California to investigate circumstances surrounding a death in Doug's family.

Carter and Lucy scramble across Chicago to find a dying girl's father who's a perfect match for her very rare blood type. Benton operates without transfusions to save the little girl's life.

Dr. Carter reads a letter from terminally ill Dr. Green to the ER staff. Dr. Weaver lashes out at a mentally challenged patient. A terminal, homeless man continues asking for Dr. Green.

Casualties of a disaster flood the ER, which is short-handed because everyone is at Dr. Carter's going-away party because he's leaving the ER after 11 years. Dr. Pratt looks for the courage to confront his father, Charlie.

Chaos reigns in the ER when two prisoners are brought in for treatment, but instead plot a violent escape. Their desperate actions place one doctor in harm's way, and forces one nurse to become a tool in their plan.

Carol's pregnancy becomes public knowledge as she learns that she's having twins. Lucy has problems trying to go off Ritalin. Peter learns Carla plans to move to Germany. Kerry finds an abandoned youngster and brings him to the ER. Mark and Elizabeth discuss their relationship. Jeanie and Reggie draw closer again.

The ER is flooded with foster care home residents, attacked by a shooter bent on tracking down his son, who , with the help of Dr. Green, was put into the foster care system amid allegations he was being abused by his father.