Dr. Will Halstead balances the stress as the ER's supervising attending physician with his complicated relationship with Dr. Natalie Manning, an attending physician in emergency pediatrics. Newly remarried, Dr. Daniel Charles remains the Sherlock Holmes of psychiatry. Former Navy flight surgeon Dr. Ethan Choi brings his battlefield skills to the front lines of Chicago's busiest ER, the go-to place for victim's of the city's gun violence. Work and home life intersect with him and April Sexton, a smart, bold and intuitive nurse with the ability to adeptly tackle the most harried of circumstances in the hospital. Sharon Goodwin, the venerable head of the city's largest hospital, is under intense fiscal scrutiny to preserve the bottom line while continuing to ensure that all patients receive nothing short of quality care and compassion. Maggie Lockwood, the charge nurse and eyes, ears and brain of the ER, is skilled and confident but finds herself dealing with profound health issues of her own.