As the 'ER' recovers from the shootout, Steve, Mary and Rafe make their way to Canada with Sam and Alex. Steve resorts to desperate measures when his partners in crime suggest that Sam and Alex are hindering their escape. Meanwhile, Weaver finds Abby passed out and bleeding and rushes to make sure the baby is safe. Dr. Dubenko and Neela struggly to stabilize Jerry's injuries.
Abby's overbearing mother arrives at the hospital to comfort her and Dr. Kovac as their son's life hangs in the balance. Sam returns to Chicago but fears that police will arrest her despite her claims of self-defense. Paramedic Tony Gates makes a risky decision with an overdosed teen. Later, Gates escorts a very drunk Neela home after drowning her sorrows at the local bar.
Pratt assumes his new role as attending but gets stuck with the task of dealing with all the new interns. When an older man is brought into the ER with congestive heart failure, Pratt assigns Gates to assess his condition.
Gates constantly finds himself stuck in the middle of his complicated living situation. After trying to juggle work and their new baby, Abby and Kovac contemplate hiring help. Dr. Pratt finds it difficult keeping all the interns and residents on track now that he is the new attending. Meanwhile, Neela is disappointed when Dr. Crenshaw assigns her menial tasks instead of the surgery she was hoping to perform.
Fresh off of her maternity leave, Abby prepares to return to work but worries that she may not remember how to be a doctor. Kovac tries to recall his treatment of stroke patient, Curtis Ames as he prepares for his day in court.
Dr. Kovac anxiously awaits the jury decision between himself and Curtis Ames but fears for the worst. Neela is tired of doing the dirty work and tries to prove to Dr. Crenshaw that she is worthy of scrubbing in for surgery. Morris prepares for his big television debut but ends up getting upstaged by Weaver. Meanwhile, Ray starts to get jealous when he sees Neela and Gates flirting.
Abby and Kovac finally decide to hire a nanny to care for their son Joe, but are troubled when they meet the potential candidates. Morris and Sam try to treat a biligerant patient that comes in with seemingly simple flu.
Abby and Kovac argue about a diagnosis when a woman comes into the ER with signs of spousal abuse. When a group of confused homeless kids enter the ER, Gates, Abby and Neela must quickly determine one child's ailment before it is too late. Meanwhile, Weaver is unexpectedly called to action while doing a news report at a school.
It's Thanksgiving in the "ER" but all is far from being quiet. Abby is about to head home when she is forced to respond to a bus crash accident on the side of a ravine. Neela accepts Gates invitation to go over to his house after work, but they are quickly interrupted by an unwelcome guest. Meanwhile, Pratt decides to discuss his brother with Dr. Weaver.
Dr. Pratt has a tough time coming to terms with his brother's newly discovered sexual orientation. Kovac spots Curtis Ames outside his apartment, but chooses not to tell Abby. Gates begs Neela to give him a chance. Meanwhile, Kovac and Gates treat a young girl who appears to have been assaulted.
A homeless boy comes into the ER and convinces Gates and Ray to help his friend in critical condtion. After treating the young victim, Gates goes againest his promise and calls child protective services.
When a patient dies after being prescribed the wrong medication, Pratt and Hope question whether they are responsible. Meg comes to County General and angrily confronts Gates and Neela about their relationship. Dr. Kovac is forced to make budget cuts that could affect one ER doctor.
Kovac gets jealous when Abby gives too much attention to a patient. Meg pulls a deadly stunt when Gates moves out of her place. As a result of one of his patients dying, Pratt finds that police are anxious to arrest him. Meanwhile, Dr. Weaver makes a decision that will change the ER forever.
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?
Abby and Sam try and treat an obnoxious, aspiring comedian with mysterious symptoms. Pratt finds himself in hot water as he gets questioned about the death of a patient. Meanwhile, Neela is thrilled when Dr. Dubenko allows her to scrub in on a kidney donor surgery.
Luka, Sam and Gates treat a woman who appears to be suffering liver failure, but is that really all there is to it? 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.
Abby and Pratt try to save a family suffering from frostbite after getting stuck in the snow. Neela gets jealous when Dr. Dubenko brings in a new surgical intern. Meanwhile, Gates struggles with the reappearance of his dad and the possibility of losing Sarah.
Sam and Morris are caught off guard, when a photographer comes in snapping photos alongside a terminally ill patient. Neela continues to feel upstaged by the new surgical intern that seems to be Dr. Dubenko's new favorite. Meanwhile, it is Sam's birthday and all she can think about Alex.
When a man comes into the ER with heart failure, Kovac and Gates must deal with the helpless father left behind. An Armenian man takes time out of his schedule and risks his own life to be a Good Samaritan. Pratt takes the high road and attempts to make amends with his brother. Meanwhile, Abby and Gates deal with the constant challenges of parenthood.
A busy ER is putting the pressure on Kovac to take care of the overflow of cases prior to being shut down for renovations. A lonely Sam befriends a terminally ill photojournalist with a negative outlook. Pratt gets a scare when his brother unexpectedly shows up in the ER. Meanwhile, the tension between Gates and his father hits an ultimate boiling point.
The entire ER is surprised when they arrive for the department dinner and find out that surprise nuptials are about to happen. Ray can't seem to handle seeing Neela and Gates together. The romantic atmosphere seems to bring everyone together.
Kovac and Abby get used to their new roles as husband and wife while Hope and Morris enjoy the honeymoon suite. Pratt hopes to change his womanizing ways as he tries to win over a new woman. Meanwhile, there's a new doctor in the E.R. -- and he means business.
Much to the chagrin of the county general staff, the new chief is ready to make some major changes in the E.R. Meanwhile, Kovac puts his honeymoon on hold while he travels back to Croatia to be with his ailing father. Gates is urgently called home when Sarah panics that she might be taken away. And a patient convinces Neela to attend an anti-war rally and consequently finds her life in peril.