While Dr. Carter pines over his separation from his pregnant girlfriend in Africa, a family of four is rushed to the E.R. after suffering carbon monoxide poisoning from their furnace -- forcing a claustrophobic Neela to accompany a newborn baby into an extremely uncomfortable hyperbaric chamber to extend its life. Elsewhere, Dr. Lewis is upbeat about her future with Chuck while Nurse Sam has reason to ponder her relationship with Dr. Kovac. In addition, Lewis and Abby treat a maniacal man who's rushed in covered in blood, while Dr. Weaver counsels a mother whose young son tests positive for leukemia. Amid the chaos, Dr. Chen returns from China with her sick father in tow.