Kovac anxiously awaits the verdict between himself and Curtis Ames but fears the worst. Meanwhile, Neela disobeys her chief's orders and also questions her feelings for Gates, and Weaver unwittingly steals the spotlight from Morris in his big television debut.

A belligerent young man who claims to have the flu turns out to be more than he seems, and presents a challenge to Morris and Sam when he refuses treatment. Abby's chance encounter with Curtis Ames leaves Kovac uneasy. Meanwhile, Pratt discovers a local church's risky drug exchange program, Neela and Gates square off, and Weaver gets an interesting offer.

Kovac and Gates treat a girl who appears to have been assaulted. When the police are no help with Ames, Kovac decides to confront the problem himself; Morris and other doctors work on a patient with an ice pick in his ear. Meanwhile, Ray tries to keep his new relationship a secret and Pratt can't fully deal when his half-brother officially comes out. Also, a new male nurse arrives.

Weaver cares for a Katrina survivor who's reluctant to have surgery on her foot; budget cuts force Luka to make a difficult personnel decision. Also, Gates' home life intrudes on the ER; and Pratt and Hope are shaken after a patient in their care dies needlessly.

Kovac reacts negatively when he sees Abby giving extra attention to a patient; Ray and Gates clash over a patient, pinning Neela in the middle; and Ben takes things to the next level with Sam. Meanwhile, Pratt is under investigation and Weaver says a final goodbye to the ER.

Kovac finds himself in a tense confrontation with Curtis Ames, and Abby must act to protect her family. Meanwhile, Neela and Gates rush to get Meg to the hospital while Sam's new home is soon under threat from fire.

Kovac and Gates find themselves with a moral dilemma when a woman comes into the ER with acute liver failure; Neela finds herself questioning what is right when Manish decides to give up a kidney to a complete stranger. Meanwhile, Ray fights to get to the bottom of a cheerleader's accidental fall; Abby gets a prediction for her future; and Alex's troubles continue to intrude on Sam's work life.

A blizzard strands a family in the snow and Abby and Pratt quickly try to save the family. A gang shooting challenges Morris and Pratt. Meanwhile, Kovac and Abby begin making wedding plans, but their engagement might not be very secret; Gates struggles with the reappearance of his father and the possibility of losing Sarah; and Neela becomes jealous when Dubenko brings in a new surgical intern.

In 12 hours, the ER will shut down. As Kovac is under pressure to take care of the patients before the final hours, he makes a pivotal decision about his future. Meanwhile, Sam befriends a photojournalist who returns only this time she's terminally ill; Pratt is concerned when his brother ends up in the ER drunk; Morris confronts Gates when he ignores his orders and angrily sends him home while Gates tries to defend his actions.

What is supposed to be a departmental dinner organized by Kovac turns out to be the surprise of a lifetime for Abby when she learns it's a surprise wedding, secretly planned by the eager groom. Meanwhile, at the wedding, ER staffers enjoy themselves with music and booze while Neela finds herself the center of unexpected attention between Gates and Ray, which leads to a drunken fight and a shocking conclusion.

The ER reopens with new changes. However, the ER is not the only thing that's changed; Kovac and Abby adjust to being newlyweds; Morris and Hope enjoy themselves at the honeymoon suite; Pratt attempts a change for a woman; Neela worries when Ray goes missing; Meanwhile, there's a new doctor in the ER and he means business; and another change may come when Kovac receives a phone call.

The ER is now in the hands of a new chief, Dr. Kevin Moretti, who is bent on major changes. Meanwhile, a phone call leads Neela to a hospital where a major shock awaits her, and a final farewell from a friend and colleague. Gates urgently goes home to stop Sarah from being taken away from him. A drug-addicted Iraq War veteran baffles Morris and Sam. Also, Kovac postpones the honeymoon and says goodbye to Abby and his son, for the meantime, while he travels to Croatia to visit his ailing father.

Abby, Pratt and Morris clash with Moretti's strict new ER procedures as victims of an anti-war rally roll in, including Neela. Gates manhandles a patient he suspects set off the explosion that disrupted the protest. A worried Dubenko lets his emotions for Neela take over during Neela's surgery. Meanwhile, the rest of the staff worry over Neela's condition.

Patients include a pregnant teacher whose student/lover was critically injured while driving; a man who is hiding a gunshot wound and a brilliant young boy who knows he is dying, but hides it from his mother. Dr. Moretti continues to remake the ER to his liking, Neela is recovering, Luka's absence is reinforced (back in Croatia and not coming back) and Sam may be starting a new relationship with a police officer.

Abby and a distracted Morris work to save two auxiliary cops brought in with gunshot wounds. Pratt treats a teen wrestler with severe vomiting, but the problem is much more serious. Sam worries over her new beau Litchman. Gates tries to help a young boy in the ICU with a deadly disease. Also, Dubenko visits Neela while she babysits baby Joe.

When Baby Joe is injured by a fall at the playground and rushed to the hospital, Abby is unable to reach Luka to tell him.

The city suffers power outages during an unseasonably hot spell. Nursing-home patients are brought into the ER suffering from hyperthermia. Abby and Pratt disagree on the diagnosis of a fussy baby. Abby falls back to old habits and quickly spirals down to rock bottom on a night she'll forever regret.

Dr Wexlar is made interim ER chief while staff deals with an industrial accident that leads to a hate crime.

Dr. Pratt applies for the job of ER Chief and gets turned down. This causes him to give 2 weeks notice. A female soldier, home 2 weeks from Iraq, is 2 months pregnant and her husband demands an explanation. Neela's cousin has arrived from London for an extended visit and gets pursued by both Dr. Morris and Harold Zelinsky. After 9 years absence, a fall in gym by her son brings Jeanie Boulet back to the ER. Not only is she troubled because of her son, but the disorientation of knowing virtually no one on the current staff does not help.

Abby returns to work; Luka applies for a job elsewhere; the reason behind a brash doctor's being at County is revealed.

A young couple is choppered to County after a car accident, and one of them has a gun. A boy who wants to be a clown is injured in a unicycle mishap, but his father considers him a mathlete and wants him to go to MIT. Pratt visits Bettina in the hospital, but she tells him off.

A young woman with a failing liver has a difficult reunion with her parents, whom she has not seen in six years. Abby receives a job offer. Brenner isn't nice to Laverne after they sleep together.

In the season finale, an ER patient with a mysterious past is afraid that people are trying to kill him. Dr. Moretti returns, trying to make amends for wrecking the marriage of Abby and Luka. Neela makes her way through a difficult M&M conference. Morris treats a woman with lupus who has an attractive daughter.

When a thirteen-year-old gymnast is brought into the hospital after having supposedly fallen off a wall, Dr. Banfield and Dr. Gates must sort out whether abuse is involved.

Patients include an 18-year-old who was stabbed with a fork at his school, and a man shot by a cop at a Halloween party. Meanwhile Sam is annoyed by Gates and Daria.

Both Morris and Neela have authority issues with Dr. Banfield and Gates upsets Sam.

A woman who broke her leg while trying to escape a house fire is brought in with her husband. The husband, Mr. Lotery did not let the paramedics to check him over. Then his brother-in-law arrives, saying that he predicted that something like the house fire would happen - it was actually an arson. Mr. Lotery's brother-in-law becomes aggressive and accuses him of being a pervert, specifically a pedophile. Mr. Lotery denies the accusations. He was sued but found not guilty. When Mr. Lotery is waiting for his wife who's in line for X-ray, he has the chance to calm down a young girl who is afraid of needles. When his brother-in-law sees this, he brutally assaults him, while Dr. Brenner calmly watches nearby... Meanwhile, Neela gets sued for malpractice.

As a snowstorm hits Chicago, Sam's son Alex crashes a car and ends up in critical condition in the ER. Neela gives a deposition in the malpractice suit against her. Dr. Morris and Dr. Banfield are both at a medical conference in Omaha, and when the snow cancels all flights out they share a memorable and surprising evening.

The police wheel in a casualty of a drug deal-turned-shoot-out. They also bring in an injured woman who was the shooter, plus a pair of wounded brothers who were shot by the man who was shot dead. A 13-year old girl with sickle cell disease is brought in because of abdominal pains; Neela takes her case while Tracy learns from her. Banfield's pregnancy test is negative, which leads to a discussion with her husband and a visit to a specialist.

A girl who was hit by a car while riding a bicycle is treated in the ER. When her boyfriend turns up, it seems it may not have been an accident. While a lottery has made millionaires of several nearby convenience store workers, Dr. Banfield and her husband are at the fertilization clinic hoping for their one in a million chance. And as an older woman is brought in assisted by her on-again, off-again husband, three love stories continue in the ER: Dr. Morris meets policewoman Diaz again, Sam discovers that Tony has been seeing Daria, and Neela plays it cool with the returning Dr. Brenner.

A single mother is hurt in a car accident, and must find someone to take care of her daughter. Gates treats a 78-year-old man who refuses surgery that would save his life. Meanwhile Morris's afternoon date with Claudia is not what he expected.

Dr. Carter returns to Chicago and talks Dr. Banfield into allowing him to pick up a number of shifts (without pay). Other happenings include Banfield's dogged pursuit of motherhood, Neela's intensifying personal relationship, and Archie's involvement with a patient who was probably beaten while in police custody - with his new girlfriend the detective standing by.

Banfield and her husband look into adoption, while Carter adjusts to a changed ER. Sam's mother comes into the ER in an altered state of mind.

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.