ER (OV)

For the emergency room personnel and doctors of Chicago's County General Hospital, the difference between life and death often depends on split-second decisions.

Chaos takes over the emergency room when another hospital is shut down, overloading County General with patients.

After an enraged drug addict points a gun at Chen and other staff members, the exasperated Carter leads a divisive walkout.

Young Gallant gets upset over the callous treatment given by his colleagues to an addled elderly patient, Stella (recurring guest star DIANE DELANO), under his repeated care.

A suspicious fire on Halloween fills the emergency room with many costumed victims--some of whom offend Pratt.

Corday clashes with new surgical resident Paul Nathan regarding his intervention into the treatment of a sickly young woman, Alison, who has signed a "do not resuscitate" order.

Abby fears the worst when her brother, Eric, suddenly disappears. Carter and Chen treat a frightened Chinese immigrant nanny, Tong-Yi, whom they suspect was impregnated by her employer.

Abby's family nightmare continues as she and her mother, Maggie, search for Abby's missing brother, Eric, who Abby suspects is suffering from serious mental problems.

Abby is distressed when her troubled mother, Maggie, interferes with the treatment of Abby's bipolar brother, Eric, at a psychiatric hospital.

In this unique episode, events leading up to Christmas are shown in reverse chronological order.

When Pratt is witnessed bringing a gun into the emergency room, Carter feels compelled to defend him. However, Pratt's erratic behavior makes Carter reconsider.

Weaver confronts a dilemma when an influential alderman, John Bright, seeking treatment after a fall, tests positive for syphilis--potentially damaging information that could become public.

Pratt is overwhelmed when his developmentally disabled brother, Leon persuades him to treat a gravely wounded robber who duped Leon into participating in a crime.

Abby is distraught upon learning that her emotionally troubled brother has gone missing while piloting an airplane. Desperate Romano receives some depressing news.

Abby becomes disturbingly close to a mental breakdown as she copes with a multitude of problems, including her missing pilot brother and needy mother, Maggie.

Pratt tries to keep Gallant from overreacting when they are apprehended and questioned as possible suspects in a murderous rampage at the diner near the hospital.

Weaver gets into trouble when she agrees to secretly treat the lover of her powerful new patron, Alderman John Bright, for syphilis.

Newly transferred to Chief of Emergency Medicine--and furious about it--disabled former surgeon Romano expresses his disdain and lack of detailed knowledge of emergency room procedure.

An overmedicated psychotic patient, James, threatens Abby. Also, Abby learns news about her missing brother, Eric.

Kovac defies the rules to get a dying Croatian boy to Chicago in a race to save his life.

In the Emmy Award-winning series' landmark 200th episode, an innovative dual storytelling device contrasts Pratt's night shift with Carter's day shift.

In a special episode, Carter travels to the war-torn Congo as part of a voluntary medical program. He finds primitive Third World facilities…