Camille serves Aaron with divorce papers; Phillip benches Arthur from further surgery when Arthur's resting tremor begins to endanger patients; Aaron removes a brain tumor from an elderly patient; Jeffrey and Aaron separate conjoined twins.

Arthur nearly fires Danny for failing to adhere to triage protocol, thereby delaying the treatment of a critically injured prostitute with AIDS; Phillip becomes the acting chief of staff after Hackett suffers a fatal heart attack during a little afternoon delight with Angela in the MRI room; Jeffrey and Arthur argue over the future of a baboon with the potential to prolong the life of Jeffrey's patient with heart failure and Arthur's patient with AIDS.

Jeffrey tells Nadine about Laurie's schizophrenia and the death of his son; Aaron and Camille grieve about their impending divorce; several members of a family of trapeze artists are brought into the hospital in critical condition after a devastating accident during a circus performance; one of Aaron's former patients reveals his bigotry when he refuses to allow Nadine to remove his diseased gall bladder and insists that Aaron or another Jewish surgeon perform the procedure; Jeffrey exhibits signs of a meltdown when, in the space of a few hours, outrageous conduct in a nightclub gets him mistakenly arrested for soliciting a prostitute and he vandalizes the car of a man who stole his parking space; Phillip incorrectly attributes Aaron's angry outburst at one patient minutes after losing another young patient in surgery to tensions with Camille, and threatens to fire Camille if there's a recurrence.

Phillip's religious beliefs and Jeffrey's grief over the death of his son put them on opposite sides of whether to convince a young mother to remove her infant from life support so that her daughter's organs can be donated to save the life of another baby; Karen deflects a flirtation from Jeffrey, but romantic sparks fly between her and Aaron.

Aaron, the staff, and the patients are caught in the crossfire when Antoine Metcalf, a gangbanger and career criminal, follows his latest victim into the E.R. to finish off the job he started, and sprays a room with automatic gunfire before hospital security shoots him down; Karen joins the staff, and successfully teams with Paula to remove hematomas that are preventing Marcus Lavelle from walking, but the trauma of witnessing his mother's being injured in the E.R. shooting leaves the little boy afflicted with hysterical paralysis and still unable to move although the surgery has left him physically fine; reluctantly operating on the shooter, Aaron jokes about how easy and perhaps appropriate it might be to cause Metcalf's death through a surgical hiccup, a remark which comes back to haunt him later when Metcalf dies soon after surgery and his family sues Aaron and the hospital for failure to provide adequate care; Arthur engages in a little ex parte communication to put in a good word

After Karen begins having seizures, Aaron discovers that she is terminally ill from the multiple brain metastases of a melanoma; Jeffrey resents having to perform surgery on a mobster about to enter the witness protection program; when the residents attempt to pull a practical joke on Jeffrey, they unwittingly provide comfort to a dying Karen.

Jeffrey strongly objects when his old nemesis is hired into the plastic surgery department, but they are able to set aside their differences to bring some peace to the mother of a young girl who dies during surgery; a nurse impedes Aaron's plan to allow Karen to die peacefully.

Camille has an innocent and unavoidable mishap in the operating room during a heart transplant on the rabbi who performed her wedding ceremony to Aaron, and blames herself when the rabbi dies later, even though her mishap had nothing to do with his death; an inexperienced new nurse stands up to Arthur; wracked with guilt, Camille reveals the operating room mishap to the rabbi's widow, and only Alan's ingenuity in demanding an autopsy keeps the hospital from a major lawsuit; Aaron and Camille have it out over his lack of emotional support after the rabbi's death, and each of them admit to the hurt caused by their divorce.

Tensions run high as hard truths ring out when Jeffrey, Danny, Camille, Maggie, Aaron, Arthur and Phillip are quarantined in an empty operating room after a possible exposure to Ebola; Jeffrey and Danny perform an emergency bypass after Arthur has a massive heart attack; Aaron and Camille reconcile.

The staff has its hands full when a man suffering from the after-effects of taking amyl nitrite suffers one complication after another, thereby necessitating multiple surgeries, and Alan takes one for the team right on the nose when he strains credulity in attempting to put the patient's situation in the best possible light; Geri and Jeffrey make peace; Camille contemplates having some plastic surgery after Aaron suffers from performance anxiety on their first post-reconciliation date; Jeffrey agrees to help Laurie put on the Institute's Christmas concert, but the preparations for the event begin to overwhelm her and put additional strain on her already fragile state; Danny and Maggie can't keep their hands off each other; Jeffrey confesses his despair about Laurie's condition and its effect on his life to Camille.

Phillip is unable to save a promising young boxer who succumbs to the fatal effects of steroids his father gave him to enhance his performance in the ring; a pregnant young teenager carrying a baby with a heart defect seeks Alan's help when she is unable to find adoptive parents for her infant; Aaron fires Angela after his tax audit reveals that she's been embezzling money from his pension plan.

Billy Kronk, a hotshot young surgeon and recreational hockey player, arrives in the E.R. with a critically ill teammate and immediately takes charge, steamrollering over Phillip; Alan deflects a suit by Nabbott, but not before bristling at Harold's ""toad"" routine in court and being thrown into jail for contempt; Billy convinces a psychotic mugger with a history of pica who has bitten off the finger of a concert flautist during a robbery to submit to an endoscopy to retrieve the digit; as Geri successfully completes the reattachment, Billy and Phillip discover a second finger in the thief's digestive tract, and realize that the musician has been given a digit belonging to yet another of the mugger's victims.

Laurie asks Jeffrey for a divorce so that she can marry Gilbert Weeks, a lawyer who is also a patient at the Institute; spurred by this news, Jeffrey suggests that Aaron perform an experimental procedure which may cure Laurie's schizophrenia; fearful that Laurie will no longer love him if she is cured, Gilbert goes to court to stop the procedure, citing Jeffrey's conflict of interest and contesting his guardianship of Laurie; although she is torn between the two men that she loves, Laurie decides that her future is with Gilbert and declines the surgery; Billy becomes a member of the staff, and agrees to do a consultation on Tamara, a teenaged patient of an old friend, Dr. Dennis Hancock; after Tamara is diagnosed with breast cancer and refuses to have a mastectomy and reconstructive surgery despite warnings from Billy and Geri that she will die without the surgery, Dennis uses just the right approach to change her mind and allay her fears of disfigurement.

When the gun belonging to a critically wounded police officer drops out of his holster in the E.R., the distraught brother of a man waiting for a donor heart picks up the weapon and threatens the staff unless his brother receives an immediate transplant; as Aaron and Danny operate on the wounded officer, one of the exploding bullets with which he was shot goes off and severs two of Danny's fingers; Geri performs a successful reattachment, but Danny may be facing the end of his career as a surgeon.

The staff works to save a young boy who was submerged in a frozen lake for several hours; Jeffrey and Geri have a little digestive mishap on their way to pursuing a relationship; Dennis fights to get an experimental treatment for a patient with AIDS, and finds an unexpected ally in Alan.

An explosion sends a dry cleaner to the ER. Dr. Kadalski is pressured to change his unorthodox methods when he treats a man who compulsively pulls out his hair. A fearful Birch lets off steam at Jeffrey as baby Alicia's condition worsens.

Dr. Kronk's feelings towards his girlfriend undergo changes when he find out about her past. Geiger's heart patient develops an aneurysm which would take him off the heart recipient list unless highly experimental methods are tried. Meanwhile, Dr. Hancock's ejection from his clinic leads to bringing the HMO provider into the courtroom.

Dr. Kronk makes a rushed decision to rescue a man by amputating his leg with a chainsaw, only to discover later that the man is a place kicker. A friend of Aaron's with Parkinson's disease comes to him for an operation...bringing his own donor material. A ex-nurse is admitted into the hospital and is given special treatment by Dr. Nyland, whom she used to date.

When the Board of Health closes the hospital doors after several patients die from a deadly staph infection, the staff scrambles to find the source of the infection; Jeffrey and Geri help each other work through feelings of grief, loss, and guilt.

A troubled Dr. Geiger seeks a blessing from his institutionalized ex-wife so he can continue his relationship with Dr. Infante. A dying AIDS patient hopes Hancock can arrange a surgical procedure that would allow him to see one more sunrise.

Following Dr. Joseph's witnessing of Dr. Geiger's actions, the medical board suspends him until his case can be reviewed. However, there is some disagreement among the hospital's staff as to whether or not the suspension is in their best interests.

Dr. Nyland pulls a switch with Dr. Kronk in order to avoid a charity function, but they have to face the consequences over somecmisunderstandings. Misunderstanding fills Aaron's life when his father barges into the hospital with a patient who is also his fiancee. Geiger finally understands that he may be causing more ripples than he thought.

Diane helps her friend Allison harvest sperm from Allison's comatose husband before his life support is turned off; Aaron realizes that the reconciliation with Camille isn't working, and they agree to go through with their divorce; Billy takes Danny to task over his medical mistreatment of a mentally unstable woman; Jeffrey and Kate manage to put aside their differences over her cost cutting proposal for the hospital long enough to save the life of a young pre-med student; Alicia is christened.

Dennis struggles over whether he should listen to his gut, or to Jeffrey's advice, in treating a man who doesn't speak English; Aaron is upset when Alan gives Camille advice about their property settlement; after Billy recommends amputation to a man with a gangrenous leg, Diane offers the use of maggots as an alternative treatment, but the patient has a great deal of difficulty in overcoming the ""ick"" factor of Diane's suggestion; Phillip seriously injures his opponent in a charity boxing match; Aaron and Camille sign the papers that finalize their divorce.

Billy arrives home just in time to save his dog Gordie from the fire that's engulfed his apartment, and ends up rooming with a reluctant Danny until he can find a new place to live; when a teething Alicia keeps her father up at nights, an exhausted Alan is thrilled when Diane offers to help out; when a racist teenager on the transplant list refuses the heart of a murdered black teenager, the hospital offers it to another candidate, but the boy's mother sues to have the heart transplanted into her son; Alan decides to get back into the social swing by asking Diane out on a date; Kate's inattention to pre-op labs results in the post-op death of the transplant patient; Danny overcomes his dislike of Gordie long enough to notice that he's critically ill, and by acting quickly, saves the dog's life.