CBS opens the doors of one of the most congested and undermanned emergency rooms in Los Angeles Wednesday night in the pilot episode of medical drama series "Code Black." 

Based on the critically acclaimed and similarly titled documentary created by Ryan McGarry, the series will center on the drama behind the everyday struggles of the doctors and nurses of Angels Memorial Hospital as they make the most of their extremely limited resources and manpower to cater to a huge number of patients.

Spearheading the never-ending chaotic events at the Angels Memorial Hospital ER is Residency Director Dr. Leanne Rorish (Marcia Gay Harden). She became famous because of her high success rates in performing high-risk procedures in the hospital's trauma area called Center Stage. Dr. Rorish is assisted by first-year residents Malaya Pineda (Melanie Chandra), Christa Lorenson (Bonnie Somerville), Angus Leighton (Harry Ford), and Mario Salvetti (Benjamin Hollingsworth).

Aside from the residents, Dr. Rorish gets the support for all the daunting ER tasks from her trusted friend, senior ER nurse Jesse Sallander (Luis Guzman). More drama comes whenever Dr. Rorish's "cowboy" approach is questioned by her colleague Dr. Neal Hudson (Raza Jaffrey). They would always clash because of her carefree, devil-may-care attitude, while he likes to strictly abide by the rules.

The series premiere will showcase all sorts of medical cases in rapid succession, including a gunshot victim who is bleeding to death, a father in his death bed, an old patient who is having difficulty remembering everything around him, and an emergency child delivery under extremely difficult circumstances. But things will not stop there.

Rorish will be seen urging her ER team to work double time to be able to cure as many patients as they can. "Life is measured here in split seconds," the lead doctor shouted as another patient is wheeled into the room. "Hesitate and people die."

"Code Black" premieres 10 p.m. EST on Wednesday, Sept. 30, on CBS. Those who cannot catch it on TV can watch the pilot episode online via the official CBS website.