When lives are on the line, dedicated doctors, nurses, and staff of Chicagos busiest trauma center are the ones to trust. In the engrossing second season, big changes put the ER on an emotional collision course. A slew of both professional and personal issues, from legal setbacks to romantic entanglements, illnesses, and the elusive work-life balance, threaten to affect those trying to maintain cutting-edge medicine with care and compassion.