A worker from a car parts factory, brought into the ED after an explosion at her workplace, is discovered to have a bizarre but deadly injury that could spell disaster for her as well as the entire Emergency Department. The scenario takes all of Frank and Mike's ingenuity and courage to come up with a solution. And that solution will see Mike putting his life on the line, giving him reason to make a radical decision about his future. A young woman, Morgan, is suffering from severe hypothermia after a camping trip went wrong and the ED team wrestle with balancing the risk of cardiac failure over the risk of brain damage. Bart, however, has his own agenda in play and Charlotte fears he isn't doing himself or the patient any good as a result. Adam's persistence with a "Frequent Flyer" patient puts him at loggerheads with both Frank and Gabrielle. Frank is surprised by a visit from Amy, his niece, who wants her job in the ED back.