Abby and Neela are assigned to a month-long rotation in the neonatal intensive care unit where they experience emotional roller coasters while caring for the sick infants.

Neela starts a new job in the emergency room after working at the convenience store near the hospital. On Neela's first day, Pratt expects the interns, Abby, Ray and Neela, to take on a large patient load during their shifts. Pratt turns processing the patients into a competition, in which Ray is clearly going to be the winner.

While examining a young boy, Pratt finds a suspicious gash across his chest and calls Wendall for a consult. Kovac and Pratt examine a man who was shot when he confronted his boss with a gun. Jake tries to convince Abby to date him despite his being a student.

Sam's ex-husband shows up and wants to take Alex on a trip. Gallant is back and Neela hopes to see him before he goes back to Iraq.

Jules 'Ruby' Rubadoux is back in the ER. He's still angry with Carter about the death of his wife.

Sam and Luka go on the search for her runaway son, Alex. Meanwhile, Pratt and Lewis guide Abby, Neela and Ray, who have become R2's, on how to teach the new interns.

An unexpected visitor puts Clemente in the middle of a domestic dispute. Meanwhile, Luka and Abby await test results on their unborn child; Neela struggles with her surgical elective and Pratt ends up with an unexpected suitor when he participates in a charity bachelor auction.

Abby and Luka desperately try to keep a young woman brought into the ER with stab wounds to the neck alive. As her condition begins to worsen, Clemente steps in and tries a risky procedure on the girl in order to save her life. Meanwhile, Neela pulls an all-nighter in preparation for a speech at a surgeon's convention, Ray treats a man claiming to have swallowed a bottle of pills, and Sam decides to take a part-time job with Richard to help her with childcare expenses.

As Abby and Luka cope with their newborn's life and death struggle, the couple is shocked to receive a surprise visitor: Abby's mother Maggie. Meanwhile, Sam fears the prospect of criminal charges; Neela discovers that Tony Gates will be joining the ER team as an intern and Morris gets his job back while Weaver gets demoted.

Thanksgiving at County is quiet, with the normal number of routine (or nearly so) emergencies. But Abby makes up for the lack of excitement while returning to the hospital as the doctor on a helicopter transport.

It's Christmas in the ER. A homeless boy sends Gates and Ray on a mission. Meanwhile, in the ER, Neela oversees an unusual kidney transplant case; Sam takes a stand when a patient is dumped in an alley by another hospital; and Morris plays Santa for a special girl and learns the meaning of Christmas.

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 cheerleaders accidental fall; Abby gets a prediction for her future; and Alex's troubles continue to intrude on Sam's work life.

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.

Moretti begins to make his presence felt, as he implements changes in the way patients are seen. The ER staff differ on how procedure when a patient comes in with a bullet in him needed as evidence. Neela finds herself the object of more attention that she wants, or needs. Abby had passport woes, and struggles with the changes being made. Pratt and Morris find themselves forced to defend their actions, Hope prepares for a new mission, and Gates finds himself labeled the reject in his new assignment.

Morris and Pratt cram for their medical boards when Morretti brings in a new attending physician to help with the load. Sam and Abby work on an attention-hungry patient who comes into the ER with elusive symptoms.

Neela's short visit in Ortho turns into a game of hockey. Bettina wants to take her relationship with Pratt to the next level, but Pratt is not keen on the idea. Gates and Sam disagree over a patient. Julia provides some spiritual guidance in order to ease a prison doctor's bad conscience.

When a drunk patient is admitted to the ER, his actions endanger everyone at County. Pratt is still pursuing his dreams of becoming Chief of the ER, and Gates is worried about his future with Sam. Luka unexpectedly runs into Dr. Moretti.

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 source.

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.

It's Valentine's Day. Dr. John Carter is back at the County. Brenner and Neela are getting closer. Dr. Banfield is having a hard time trying to have a baby. And Puck and mushrooms may not be a good combination.

Carter finds himself struggling with County's new technology and procedures. After becoming frustrated with the in vitro-fertilization, Banfield and her husband discuss adoption as an option. Sam's mother arrives in an altered state of mind.