Healing is teamwork and science. Instant decisions and best guesses. Joy one moment, tragedy the next, 24/7 readiness. It is learning, always learning. County General is a teaching hospital. And each day it presents its weary students and dedicated doctors with an unexpected instructor called experience. The ambulances are ready to unload more compulsively watchable tales of drama and triumph. Carter and Kovac return from Africa: one with a new love and both lucky to be alive. Romano, at the ER, is not so lucky. Med student Neela Rasgotra arrives from India by way of London. Med student Abby Lockhart arrives by way of the ER nurses' station. Do they have what it takes? Old Man Experience awaits them.