A series about the emergency room in a large Chicago teaching hospital in which the overworked and underpaid residents of County General Hospital make life-and-death decisions every day. The Staff includes Dr. Mark Green, a senior attending physician whose dedication to his career lost him his marriage; Dr. Peter Benton, an intense surgeon who must take care of his hearing-impaired infant son; the well-intentioned Dr. John Carter, a third-year resident in emergency medicine; Carol Hathaway, compassionate head nurse who is pregnant with twins; Jeanie Boulet, an HIV-positive physician assistant; Dr. Kerry Weaver, a determined attending physician whose intense professionalism often irritates her colleagues; Dr. Elizabeth Corday, a dedicated surgeon from Great Britain; Lucy Knight, a fourth-year medical student; and Dr. Robert Romano, the self-promoting new chief of staff.

Joining the staff are Janko Pavic, an ER attending physician moonlighting at County General and Dr. Cleo Lynch, a second-year resident in emergency medicine and pediatrics.