A busy Dr. Greene goes all day in solving his patients' problems until he encounters the case of a pregnant woman suffering from complications that threaten both her life and her unborn baby's.

Deb and Carter compete furiously for procedures after Benton announces their books are due a week earlier than previously announced. Deb commits a nearly deadly error on a patient while trying to keep up with Carter. Doug's relationship with Diane Leeds grows. Peter and Jackie decide to put their mother in a home. Dr. Greene is put on trial, so to speak, in the M conference for Jodi O'Brien. Chloe returns.

Susan has her hands full with a pregnant Chloe. Benton goes to dinner with Jeanie. Greene further alienates Swift when he decides to honor a family commitment rather than stay longer at the ER to help him. Carter makes a good impression on Dr. Swift. Doug turns down an offer to "celebrate" with Linda Farrell, instead getting more serious with Diane as he agrees to coach Jake's Little League team.

The ER treats victims of a gang shootout. Carter arrives late and unprepared for his new position. Mark learns all about being an attending, including senior staff's habit of bad-mouthing the residents, particularly Doug Ross. Mark hires a new chief resident, Kerry Weaver. New third year med students arrive to complete their ER rotation.

Benton goes into Carla's private hospital files when he fears that something may be wrong with their baby; Jeanie treats a suicidal woman who reveals a surprising secret; and Greene learns that Rachel has been lying about her health.

Benton tries to find out if everything's OK with Carla's baby. Carter tries to get a man operated, despite the fact Anspaugh thinks he will die no matter what.

Jeanie asks Greg to help Al get into a special AIDS-program at the hospital. Olbes brings in her grandfather, who had a stroke.

It's Carol's birthday, Mark is returning to work after being assaulted and Carla goes into premature labor.

On Thanksgiving Day Carol goes into labor. She's able to get to the ER only thanks to Luka's help. She delivers the first baby in the ER, but the second causes some trouble. Greene leaves Elizabeth to deal with his father and daughter, as he rushes to assist Carol.

As the result of a school shooting, Kovac and Benton care for the gunman and his victims. Abby discovers that Carter has been illegally injecting pain relievers. Greene and Weaver confront Carter about his problem, and Weaver orders him to enter a drug rehabilitation center or leave the hospital permanently.

Dr. Carter struggles with his drug dependency; a custodial strike leaves the ER cluttered with garbage; a riot at a high-school football game leaves several wounded.

A young couple cope with their baby being premature; Greene and Corday struggle with their relationship.

Chen gives birth, but insists on breastfeeding the infant before she gives it to the adoptive parents. Greene and Corday consult a brain specialist in New York City who believes the tumor can be safely removed. Stressed and tired, Carter impulsively swallows two painkiller pills but intentionally vomits them. He confesses to Abby.

As the new director of diversity, Benton studies medical school applications and discovers that his own academic record did not qualify him--he was admitted because of affirmative action. Weaver feels uncomfortable amongst Legaspi's lesbian friends. Carter treats an unvaccinated child who contracted measles.

On Thanksgiving Day, a helicopter crash outside the ER leaves several injured, and kills Dr. Romano. Alex tries to bring Sam and Luka together.

Much to Ray's dislike, a surrogate mother in labor doesn't want to have a C-section and endangers the life of the baby. Meanwhile, Sam tells Luka she and Alex are moving out. Pratt meets his half-brother and -sister, and Abby makes a difficult decision about a young boy.

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.