The hospital staff copes with the immediate aftermath of the shootout. Weaver finds Abby unconscious and Kovač tied to a gurney. Abby's trauma puts her into pre-term labor, her baby is born two and a half months prematurely. When bleeding continues, Abby undergoes a hysterectomy. Jerry's heart was nicked by a bullet and he has to have surgery, which Dubenko and Neela perform successfully. After a rough chase from local police, Steve and his partners decide to hide out. His partners want to leave Sam and Alex so Steve shoots them. He later rapes Sam and falls asleep, Sam goes to leave with Alex but then goes back, picks up Steve's gun and shoots him.

As their infant son's fate hangs in the balance, Luka and Abby struggle to make the right decisions and keep the faith. Maggie arrives, determined to help. The hospital board meets to fire Luka over the Clemente fiasco; when Weaver confesses that she, not Luka, was responsible, she is demoted to an ER attending. Sam's employer, Eliott, helps her forestall any police investigation of Steve's death. The ER struggles to get back to normal, as old staffers play new roles, and new personnel come on board.

Pratt and Kerry must adjust to new roles. It’s the first day on the job for the medical students and interns, and Neela and Gates have a tough start. A closeted, older gay man with kidney failure comes to the ER. Gates doesn't fill out his chart properly mixing up the medication he's on. Pratt gives him calcium which leads to heart failure due to the wrong medication on the chart. Gates goes against Pratt's orders and saves the patient's life, but he is brain dead, which ultimately makes things worse on all fronts, especially with Pratt.

A grandfather and grandson are injured in a chainsaw accident, Luka takes the grandson upstairs leaving Pratt to handle the ER alone, juggling multiple traumas, teaching duties and a troublesome intern. Neela mentors a new med student, and lends a hand to Pratt in a trauma. Abby goes to a “Mommy and Me” class, but it’s not all fun and games.

Award winning actor/director Forest Whitaker begins a six-episode arc as Curtis Ames, a carpenter who suffers a stroke under Luka’s care and then sues him for malpractice. In the opener, Luka and Ames square off in court as each man’s recollections of Ames’s treatment are recounted via testimony and flashbacks. Meanwhile, Luka worries about the implications of the suit and the possible outcomes. Abby returns to work and must adjust to the dramatic changes in her life. An equipment shortage hampers Pratt, Abby, and Neela’s treatment of a patient, leading them to attempt a risky procedure. Pratt’s early morning trip to the barbershop results in a new awareness of community need.

Luka gets some important news, and at the end of the day, an unexpected visitor. A collision between a motorcycle and a car brings critical patients to the ER. Luka and Ray treat the motorcycle rider, and discover a condition his wife wants kept secret. Abby and Neela work on the driver of the car, but his surgery doesn’t go well and his wife soon has troubles of her own. Pratt has a new lady in his life, and a new roommate, while Gates has a different kind of girl-trouble. The women of the ER take some time for stress relief.

A belligerent young man with the flu presents a challenge to Morris and Sam when he refuses treatment, and later turns out to be more than he seems to be. Luka and Abby’s childcare emergency means balancing baby care with patient care in the ER until a nanny can be found, but the candidates prove less than satisfactory. Luka has an uneasy encounter with Curtis Ames at the hospital, and later Abby and Baby Joe have a "chance" encounter with Ames at the park. Pratt discovers a local church's risky drug exchange program. Neela and Gates square off at an M&M.

Luka and Abby treat a man injured after driving drunk, but differ about what should be done when his wife appears to have been abused. Later, Luka receives an unsettling package and Abby meets an intriguing stranger. A group of street kids come to the ER when they think one has rabies, and find a guardian angel in blue. Pratt disappears from the ER for a community-related reason, and learns a surprising truth about a family member. Kerry’s TV appearance becomes a real emergency.

It’s Thanksgiving in the ER, and everyone prepares for the festivities. Luka and Abby's shared feast is delayed when a medical evacuation flight to transfer an older patient puts Abby in the middle of a bus crash scene where she earns the respect of the flight crew. Luka shares concerns about a worrisome former patient with the police, who have doubts about what he thinks is happening. Pratt turns to Kerry after learning about Chaz, and Gates tries to charm Neela, but Meg adds a sour note.

A teenaged girl is found in front of her school, bleeding and apparently raped. As Luka and Gates treat her, Abby and Neela try figure out the truth about what happened, while Luka must help the girl's mother, a colleague. When the police are no help with Ames, Luka decides to confront the problem. Abby's friend from Ike's returns. Pratt struggles to cope when his brother comes out. There’s a new nurse on the floor, but can he handle the ER? Meanwhile, Ray’s got a secret and Gates pours on the charm, but Neela’s not impressed.

It's Christmas in the ER again. Luka and Abby as Rudolph and his elf, visit pediatrics, while Morris learns the meaning of Christmas when he plays Santa to a special girl. Ames takes action that creates tension between Luka and Abby, leading Luka to make a heartfelt confession. Teller returns, sending Gates and Ray on a mission, while Neela oversees an unusual kidney transplant case. Sam and Ben take a stand when a patient is dumped in an alley by Mercy Hospital. Morris, after getting a visit from one of his children, gets an offer he can't refuse, but somehow, does.

Kerry gets an interesting new job offer in Miami. Budget cuts force Luka to eliminate an attending position: Kerry. As word gets around the ER, emotions run high, and the Kerry fights back. Pressed by the staff, an angry Abby confronts Luka, creating tension between them. Pratt's efforts at community service lead to an unanticipated turn of events when a patient dies from the side effects of medication received at the clinic. Later, he learns the case will be investigated, leading him confess his role to Luka, but to protect Hope. Gates' home life intrudes on the ER, affecting Neela. Morris' missing credit card has Sam concerned about Alex' role in the loss.

Divisions abound in the ER as the aftermath of Luka’s and Pratt’s actions are felt. A patient’s call creates friction between Luka and Abby. A contentious family case leads Gates and Ray differ over treatment of one child, while Luka and Abby clash when she needs help with the other. An unauthorized phone call has serious implications for Pratt. Ben takes things to the next level with Sam, but Sam’s cautious, and Ray wonders if he’s lost his chance with Neela.

Luka tries to extricate Pratt from a legal mess while Abby, confronted by a vengeful Ames, tries to reach him. Later, Luka finds himself in a tense confrontation with Ames, and Abby must act to protect her family. Neela and Gates rush to get Meg to the hospital. Sam’s new home is soon under threat from fire, but will everyone escape unscathed?

Morris becomes the man of the hour in a busy ER while Pratt must defend his actions, and accept the consequences. Luka faces the ER in the aftermath of the Ames incident. Abby and Sam treat a dying comedian who is unable to make his final appearance. Neela gets her big chance to assist on a double kidney transplant. Ray realizes all may not be lost, after all. And who makes a surprising decision at the end of the day?

Luka, Sam and Gates treat a woman who appears to be suffering liver failure, but is that really all there is to it? Luka confronts Gates when he tries to lie on a medical document. Abby treats a couple with injuries resulting from an unusual ceremony, and a fortune-teller with a prediction for her future. But what’s their secret that Luka lets slip? Neela prepares for another kidney transplant, but something seems amiss to her, leading to a confrontation with Dubenko. Ray treats the victim of an unusual fall, and Alex’s troubles continue to intrude on Sam’s work life.

A blizzard moves into Chicago, stranding a family in the snow. Pratt, Abby, Hope and Ray must struggle to save the family, and keep hope alive when they learn one member is still missing. Luka’s got a problem intern in his sights, and he’s not pleased. Later, a gang shooting challenges Luka and Pratt. Meanwhile, Luka and Abby begin making wedding plans, but is their engagement still a secret? Sam makes a difficult choice about Alex, and wonders if she’s failed him. Neela discovers she’s no longer Dubenko’s favorite, and Gates has an unexpected, and unwelcome, visitor.

Luka, Abby, Pratt, Morris and the team treat the victims of collision between a big-rig and family car, including the wife of the truck driver and the son of the car’s driver. Sam celebrates her birthday in the ER and meets photographer who changes her outlook on life. Neela and Ray share some subtle signals, but what’s up? Gates is shadowed by a medical student who notices his errors. Wedding plans continue as Luka and Abby try to decide where to be married, but someone else is handling the bachelor party.

When father-and-son (guest stars Robert and Andy Prosky) come to the ER, Luka must treat the son’s failing heart while he takes on responsibility for the father. Language presents a challenge when Neela and Abby treat a good Samaritan. Meanwhile, Pratt tries to help Chaz make a new career choice, Gates has troubles with his own father, and Sam’s got her hands full with a seminar on handling aggressive patients. And who’s the John Doe Abby’s treating, and hiding from Luka?

In only 12 hours, a pressured Luka must coordinate the emergency closure of the ER, as the team rallies to make provisions for patients. Chaz is admitted to the ER, worrying Pratt, and Ray is challenged by a young patient. Sam renews her friendship with the photographer Diana, while Gates faces new problems on the father front. At day's end, as the lights go out, Luka makes a pivotal decision about his future.

Luka’s carefully arranged formal dinner for the ER staff gives Abby the surprise of a lifetime when she discovers the real reason for the evening. Luka finds himself dealing with Abby’s reaction, but love prevails, and in the end, events come off as planned. As the celebration continues, Pratt plays an important role with a bit of panache, Morris and Hope find themselves with an opportunity they can’t resist, and Neela finds herself the center of all manner of unexpected attention.

Dr. Kevin Moretti, an ICU specialist bent on change, joins the ER team. Change comes elsewhere as Luka and Abby adjust to being husband and wife, Pratt tries to be a new man to his lady friend, Morris and Hope take things to the next level, and Ray goes missing. Later on, Luka gets a troubling phone call.

Luka postpones his honeymoon, leaving Abby, Joe and the ER behind to begin a different journey. Meanwhile, it's Moretti's first day as Chief of Emergency Medicine, and everyone feels the effects of his style, especially Pratt and Morris. Neela learns of Ray's fate, then joins an anti-war rally and finds herself in a dangerous situation. Gates faces a crisis on the home front.