Before Allen Conner can process losing his job as the head of Infectious Diseases at Bethune General Hospital (Beth-H), a massive explosion tears through the basement. Though he and Griffin work brilliantly together to treat those caught in the blast, the damage is catastrophic. Striking new ER resident Peter Cutler recruits Mel in aid of a foreign agricultural worker. Chief-of-Staff Linda Tuttle looks for a scapegoat in the wake of the explosion, while the downstairs staff grapple with loss, and Allen pursues a new position as an ER doc at Beth-H.