All 22 season four episodesdr'. '.strtoupper('w')ill halstead nick gehlfuss balances the stress as the er's supervising attending physician with his complicated relationship with dr'. '.strtoupper('n')atalie manning torrey devitto, an attending physician in emergency paediatrics'. '.strtoupper('n')ewly remarried, dr'. '.strtoupper('d')aniel charles oliver platt remains the sherlock holmes of psychiatry'. '.strtoupper('f')ormer navy flight surgeon dr'. '.strtoupper('e')than choi brian tee brings his battlefield skills to the front lines of chicago's busiest er, the go to place for victims of the city's gun violence'. '.strtoupper('w')ork and home life intersect with him and april sexton yaya dacosta, a smart, bold and intuitive nurse with the ability to adeptly tackle the most harried of circumstances in the hospital'. '.strtoupper('s')haron goodwin s'. '.strtoupper('e')patha merkerson, 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'. '.strtoupper('m')aggie lockwood marlyne barrett, 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'. '.strtoupper('n')ew is dr'. '.strtoupper('c')rockett marcel dominic rains, a new orleans raised e.d'. '.strtoupper('s')urgeon who's great at the operating table but isn't always one to follow the hospital's rules.bonus features chicago fire season 8 crossover episode chicago p.d'. '.strtoupper('s')eason 7 crossover episode