Dr. Lewis tries to get a mentally disturbed individual admitted to the psych ward. Carter has a difficult day, treating many members of wedding party, suffering from food poisoning. Dr. Ross finally visits Carol, eight weeks after her suicide attempt. Dr. Greene deals with an elderly gentleman having a difficult time letting go of his dying wife. He also discovers that Jenn passed the bar exam.

Carol returns after her eight week absence, finding Doug holding himself responsible. Carter finds himself watching over a mysterious, mentally ill singing woman. Susan clashes with Dr. Kayson over a diagnosis. Dr. Greene treats a domestic violence victim.

Carter has a difficult day when he has to identify a dead teenager and notify his parents. It doesn't help that he notifies the wrong family. Doug woos Carol, despite Taglieri's presence in her life. Benton clashes with brother-in-law Walt after he neglects family duties.

A business contractor with a bad heart gathers his family around him in the ER as he prepares for the end. Dr. Ross helps an asthmatic teenage girl when her mother doesn't have the funds. Carter worries that he may have contracted an STD from Liz. Dr. Lewis treats a teenager with alcohol poisoning. Jenn Greene prepares to move to Milwaukee.

The air conditioning quits on the hottest day in October which, coupled with closed ERs in Chicago's other two hospitals, leads to an extremely hectic day. Dr. Ross treats a six-year-old suffering from a cocaine overdose; Ivan Gregor, the liquor store owner, shoots and seriously wounds a young teenager. Susan's immature sister Chloe drops by, wreaking havoc in Susan's life. Doug picks up a pharmaceutical saleswoman, much to Carol's displeasure.

Benton and Langworthy interview for the Starzl fellowship. A drunk Chloe throws a tantrum in the hospital. Benton saves a man with a throat wound, earning Morganstern's praise. Carter has a good day, winning a bottle of champagne and getting three leads on apartments. Carol has second thoughts about moving in with Tag after a spontaneous kiss with Doug.

Carter and Benton treat a suicidal transgender woman. Doug feels like a 'kept man' in his relationship with Linda Farrell. A patient entrusts Carol with the particulars in an accident. Cvetic continues to battle his demons, ending up wandering down the middle of a crowded street.

Benton makes a critical error when he publicizes the availability of a dying man's organs before obtaining the wife's permission. Lewis discovers that Cvetic has quit his job at the hospital, moved out of his apartment, and dropped out of sight. Carter makes a move on Susan. Chloe announces her pregnancy.

Carter fumbles his way through his first look at surgery. Dr. Lewis' nemesis, Dr. Kayson, makes her New Year's Day decidedly unpleasant. Chloe announces she's moving to Texas with her boyfriend.

A case of apparent spousal abuse is not what it seems. Deb outshines Carter after he is up all night preparing for a presentation. Peter informs Jackie he's hired a helper for his mother. First Kayson's reprimand against Susan is denied, then Susan has a chance to prove herself when Kayson is brought in as a patient. Dr. Ross meets Diane Leeds, of risk management, and her son Jake.

Morganstern invites Mark to join the staff as an attending physician. Mark treats an woman with breast cancer, who begs him to kill her. Deb "wows" Benton with her amazing presentation, leaving Carter in the rear again. Benton offends Haleh, who spends her day making his job extremely more difficult. The ER gets new crash carts, which are promptly stolen by cardiology.

Dr. Hicks berates Benton when he tries to switch shifts to attend his mother's birthday party. A teenage girl, a frequent patient of the ER, is brought in for a drug overdose. Carol decides she wants to adopt Tatiana while Tag isn't so sure. Dr. Ross slugs an abusive father in the lobby. Jen accepts a job offer in Milwaukee despite Mark's offer from Morganstern. Deb and Carter await the arrival of sub-internship applications.

Mark, still upset over the loss of Jodi O'Brien, takes the night off but ends up in the ER anyway, albeit an hour late, when the new chief runs a drill at 2:00 a.m. Benton begins to realize his mother's future is not bright. Carter and Deb compete against each other. A small moon coinciding with the naturally heavy Saturday night traffic causes an exciting night.

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.

Mark and Jennifer struggle to remain together as Mark has moved in with her in Milwaukee. Doug coaches Jake's little league team. Chloe's irresponsibility wears Susan down. Carter asks Benton to fill out a recommendation for the ER sub-I. Carol and Tag try to write their wedding vows; he becomes upset when Carol invites Diane Leeds, knowing that she'll bring Doug. Peter exhibits a growing attraction for Jeanie. Susan discovers what happened to Div when she spies his picture in a cabbie's dating service photo book. The staff discovers that Carter comes from a wealthy background.

Carter faces his last day in the hospital with aplomb, harshly grading Benton on an evaluation report. He later rescinds the report after finding out that the surgical sub-I is his. Carol faces wedding day jitters, culminating in Tag's deciding to call off the wedding. Chloe disappears again, abandoning little Susie with Susan. Dr. Swift changes his mind and decides to support Mark. Jake visits Doug.