This week: Luka is sent into desperation mode after the sick child he's trying to help makes a surprise early arrival, Eric crashes Gamma's funeral, Romano's arm gets set on fire, after a young man's entire family is injured in a drive-by shooting, Carter tries to stop him from igniting a brewing gang war, Chuck and Susan make a decision about their future, and Daniel's long nightmare is over as Carter and Abby call it quits.