At the heart of the ER's controlled chaos is Residency Director Dr. Leanne Rorish (Academy Award winner Marcia Gay Harden), renowned for successfully performing high-risk procedures in Center Stage, the trauma area reserved for the most critical cases. Her four new first-year residents are Christa Lorenson (Bonnie Somerville), Malaya Pineda (Melanie Kannokada), Mario Savetti (Benjamin Hollingsworth) and Angus Leighton (Harry M. Ford). Leanne's confidante, Jesse Sallander (Luis Guzman), is an amiable seen-it-all senior nurse who manages the residents. Also working in the ER is Dr. Neal Hudson (Raza Jaffrey), an excellent physician who sometimes disagrees with Leanne's "cowboy" approach, and Dr. Rollie Guthrie (William Allen Young), the energetic, longest-serving attending. In Center Stage, life is measured in seconds, and these heroic doctors and nurses operate with speed and skill within an overwhelmed system to treat the crowds of people who are often there for one of two reasons: to die or to receive a life-saving miracle.