ER: Season 12

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.

Ray objects when a surrogate mother in labor endangers the baby's life by not wanting to have a C-section. Meanwhile, Sam tells Luka that she and Alex are moving out; Pratt meets his half-brother and -sister; and Abby makes a difficult decision about a young boy.

Luka has a very bad day: New nurse manager Eve Peyton notices he doesn't want to work with Sam and tells him so. At the end of the day he's drunk and Abby takes him home.

The rainy night brings in diverse patients, including a mother involved in a car accident with her baby, a man with a satisfaction facilitator, and a comatose patient who suddenly wakes up. Also, Sam stands up to Eve and her strict ways and Jerry gets struck by lightning.

A new attending, Dr. Victor Clemente, comes aboard and quickly makes a stir in the ER. Abby's breast cancer patient convinces her to take a long awaited test. Luka befriends a young woman who awakes from a six-year coma. Also, Weaver shows Clemente who runs the ER.

Pratt's half-brother tries to get him to make amends with his estranged father. Clemente treats an infant chimpanzee and involves Abby and Neela on the secret case. Eve promotes Sam and her first task is to fire a beloved nurse.

A kidnapped girl is the victim of police shooting. Abby is stuck in the middle of a disagreement between Luka and Clemente. Neela receives a phone call from Iraq. Later, Luka and Abby share a kiss.

The ER prepares to take in victims from a plane crash while Neela and Pratt head out to the crash site where Neela makes heroic efforts. At the end of the day Neela gets a surprising visit.

Gallant impulsively asks Neela to marry him that exact day; she says I do but soon gets cold feet. Morris stands up to Weaver on a patient's course of treatment. Luka, Sam and Clemente treat a boy who contracted HIV from his mother. Also, Abby and Luka redefine their relationship and Luka is named the new Chief of Emergency Medicine.

Pratt and Weaver try to create a Christmas miracle when they work to save a girl wounded from gunfire. Eve gets into trouble after punching a disruptive patient. Also, Abby has a special gift for Luka.

Neela treats a religious teenage girl who turns out to be pregnant. Abby and Kovac struggle to figure out what to do with her unexpected pregnancy.

Ray helps an old friend escape from her abusive father. Dubenko volunteers in the ER but can't seem to handle a slow day. Abby and Kovac go baby shopping, while Neela gets unexpected and upsetting news from Gallant.

Dr. Nate Lennox, a former professor with ALS, is brought in as the progression of his disease is chronicled through his own flashbacks as he is treated by each of the doctors at one point. As Lennox wants to give up, Abby fights to convince him to keep on fighting.

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.

In Sudan, Carter and a colleague struggle to save a woman who was raped by a band of militants. Back in the ER, Clemente asks to return to work after the shooting incident, but Kovac refuses. Meanwhile, Neela and Pratt have a work dispute, and, in a related incident, K.J.'s father shows up again in the ER.

When Abby discovers that one of her patients has contracted meningococcemia, the E.R. is briefly quarantined. Infuriated Luka suspends Pratt, who confesses that he falsified T.J.'s drunk father's blood test, which could wreck both their careers, for five days while deciding his fate. Weaver must finally chose to have hip replacement surgery which will 'affect her identity' when the pain interferes with her work, ultimately agreeing and asking Abby to take care of Henry if something goes wrong. Sam treats businessman Richard Elliott, who collapsed and offers her an intriguing job a sin)living private nurse. Neela decides to attend a support group for military spouses, where her skeptical view of the war turns the meeting into a pacifism-patriotism debate.

Luka and Abby's try feverishly to save young Turkish refugee Hana Kardatay with multiple stab wounds. Croatian ex-refugee Luka and her mother connect as she shares her experiences from her former life in Turkey. As the girl's condition worsens, Clemente steps in and decides to try a risky procedure; surprisingly, his and Luka's first effectively collaboration. Overprotective brother Mahir's dark secret is betrayed. Ray treats a man who claims to have attempted suicide by pills, hiding a less morbid secret escaping the psychiatrist. Neela pulls an all-nighter in preparation for a speech at a surgeon's convention but is disappointed when her speech goes awry, fainting when falsely accused by activists, consoled by mentor Dubenko, and tells Ray she must move out. Morris' past catches up with him in the red-haired shape of his donor sperm kids. Sam accepts a part-time job as Richard Elliott's in-living nurse.

A case involving two teens injured in a car accident baffles the doctors, trying to determine why the girl is unconscious and her male companion is so hostile toward the police, before Ray discovers he's deaf, and the cops (not understanding his sign language) jumped him. Neela copes with a visit from Gallant's bickering parents and Morris gets a tempting job offer from a pharmaceutical company. Olivia learns of Pratt's philandering. Luka tells Abby that Carter has asked him to join him in Darfur, but when he realizes Abby is worried, he tells Pratt to go and responds to Pratt's protests it's not a request but an 'or-you're fired' order. Sam enjoys the perks of working for Elliott. Ray struggles with some unresolved feelings for Neela who decides to move back to Abby's apartment.

Jodie's cop husband's harassment makes sleepless Clemente ever more twitchy, mistaken for a junkie, arguing with everyone, at times grossly. Morris has taken a job with a major pharmaceutical company, so happily counts his last days as chief resident at County, refusing hard cases. Clemente wants to release Sam's ex-boyfriend Steve, who arrives at the ER complaining of a stomach pain, but Neela's pleas to keep him in the ER is proven correct: he has appendicitis. Morris wins an argument with surgery bitch Dr. Albright about a patient, and afterward they make out. After hip replacement surgery, Weaver no longer needs a cane. Pratt arrives in Darfur, greeted by Carter, quickly noticing the scope of the horror there.

Pratt gets to work in Darfur alongside Carter and his co-workers, but is troubled by great number of people needing care and finds himself making a dangerous journey.

Pratt struggles to get a straight story when two abused boys come into the ER with their father. Two U.S. Army officers enter the ER.

Chaos reigns in the ER when two prisoners are brought in for treatment, but instead plot a violent escape. Their desperate actions place one doctor in harm's way, and forces one nurse to become a tool in their plan.