ER

Abby awakens after the ambulance explosion and rushes to check on Pratt; Sam and Gates rush to the scene; Morris and Neela struggle to keep up with Pratt's injuries; Abby treats a young girl injured during the blast.

Everyone in the ER is trying to cope with the loss of their colleague. The staff feels defensive toward the new Chief and her tough disposition. Gates and the new interns treat a bio terrorist, who has a lethal secret that endangers them all. Neela makes a great effort to get Dubenko back on the surgery staff, and gets help from an unexpected souce.

When a gunshot wound victim arrives, the new chief and Abby butt heads on how to treat the patient. Abby comes to Sam's defense when she goes before a nurses disciplinary board.

Dr. Banfield defends herself during a mugging. Dubenko returns to work, due in no small part to Brenner's organized protests. A young gymnast comes into the ER with injuries consistent with a fall, but Banfield and Gates each think a different family member may actually be to blame. Sarah neglects to ask Gates's permission before getting her tongue pierced.

It's Halloween night, and the interns continue to be paired with the residents. Gates's teaching methods with Daria, and her responses, belittle Sam. A school fight results in a stabbing and a nose that won't stop bleeding, with Brenner treating the victims and being deeply affected by the truth behind their confrontation. The staff, especially Neela, are enthusiastic about a surprise visitor. Gates gets locked in a maintenance area with a quiet young boy.

Chaz, now a med student, begins his ER rotation. Morris takes him under his wing and shows him some risky procedures, endangering a patient and raising Banfield's ire. Neela becomes upset when Banfield questions her authority and skills in front of her intern. Gates invites Sam and Alex to move in with him and Sarah.

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 man acquitted of child molestation comes into the ER with his wife, who was injured when their house was set on fire, drawing Brenner's hostility. Later, the man's interest in a young girl leads his brother-in-law to beat him, nearly blinding him. When Brenner becomes emotional while the man is treated, Morris confronts him, leading to an emotional revelation about Brenner's past. Neela's frustration with her intern reaches the boiling point, and Dubenko teaches her a lesson in the importance of teaching and mentorship. Gates continues his search for the missing veteran.

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.

A package for Morris from his deceased father is delivered to the ER. Sam has some anxiety over Alex being removed from the ventilator. A woman with a high risk pregnancy worries that she will be deported. An old friend returns to celebrate the holidays. Frank and Drs. Sanchez and Wade accidentally get cake with cannabis in it.

When a drug deal goes bad, two brothers sustain serious injuries and are brought to the ER. Tensions continue between Gates and Sam, coming to a head when Tony is the last to know Alex is about to be released from the hospital. Neela has to tell a young girl with sickle cell anemia that she must have an operation, and the case leads her to consider specializing in pediatric surgery. A feisty patient takes Morris into her confidence. Banfield ponders her choices about expanding her family.

Neela has recurring dreams about trying to save a girl with sickle cell anemia. In them she also goes to an attending interview and sees an old colleague, has conversations with Ray, welcomes Brenner back from Australia, and assists Gates and Banfield in trying to save a "dream runner" who jumped out of a window during his sleep.

Morris faces a complicated case involving a young girl hit while riding her bicycle. Gates finds it very difficult to let go of his feelings for Sam. Neela becomes quite flustered when Brenner returns from Australia. Dr. Banfield and her husband are at the fertilization clinic hoping for their one in a million chance. And an older woman is brought in assisted by her on-again, off-again husband.

An elderly man is brought into the ER after being mugged, and sees things as if it were the 1960s. Sam's sister shows up unexpectedly. Brenner and Dubenko clash while treating a mother thought to have late stage cancer. Dr. Morgenstern returns to the ER to assist a former mentor who is seriously ill.

A car accident in the ambulance bay injures a woman with a young child and leaves the mother in need of surgery with a significant recovery time. Brenner has difficulty finding a family member to care for the daughter. Gates treats an elderly patient who refuses treatment because he's afraid his condition will prolong an inevitable death. Morris impresses Claudia and her family. Neela tells Brenner about her job offer from North Carolina.

Valentine's Day in the ER finds Neela spellbound by Brenner. Determined to have a baby, Banfield comes up with a plan but has difficulty getting her husband on board. Neela performs surgery on a young girl's mother. Dr. Carter surprises the staff with a visit to the ER. Gates treats a strange patient who may have ingested a toxin while hunting for mushrooms.

The Banfields explore their options with an adoption agency. Carter holds his own in spite of the procedural and technological advances made to emergency medicine since he's been gone. Brenner has concerns about Lucy's foster family. Morris treats a couple who takes his advice a little too far. Sam gets quite the shock when her mother comes into the ER. Neela makes a decision about her future. Banfield discovers Carter's secret.

A camera crew shooting footage for a documentary interviews members of the ER staff. Detective Claudia Diaz is brought in, critically injured with gunshot wounds. Neela laments the lack of communication between her and Brenner. Sam struggles to reconcile with her mother. Carter's condition worsens quite suddenly.

A girl drops off a sick baby at the ER and then leaves; Carter may get a kidney transplant; Gates and Daria care for an elderly woman with multiple sclerosis; Neela and Sam are in Seattle to transport a heart for Joanie Moore, while Doug and Carol are concerned that the donor's grandmother might not consent.

It's Neela's last day and everyone in the ER seems to have forgotten that she is leaving. Neela proves she is ready to be an attending when she and Dr. Dubenko argue about the treatment of two surgical cases. Meanwhile, Brenner has an epiphany about his troubled past.

Many of the ER doctors and nurses help out at Camp Del Corazon, a camp for kids who have had open heart surgery. Working along side the camp counselor, Morris and Brenner make a huge impact on several kids at the camp. Meanwhile, Dr. Banfield and her husband feel their adoption dreams slipping away when a young mother comes back for the child she abandoned in the ER.

Gates works on a young teen brought in with alcohol poisoning after playing a deadly drinking game with friends. Dr. Carter opens a new medical facility for the underprivileged in Chicago and some old friends from County General all come to show their support. It's Sam's birthday and Alex and Gates surprise her with a special gift. Meanwhile, Carter works with an intern to save a mother in labor with twins.