S2, E12: Dr. Manning (Torrey DeVitto) and Dr. Charles (Oliver Platt) treat a teenage girl with a rapidly changing set of symptoms that has everyone perplexed. Dr. Choi (Brian Tee) and medical student Jeff Clark (guest star Jeff Hephner) encounter a 19 year-old tough guy who is brought into the hospital in severe distress. Once they establish the cause of the pain, the situation quickly turns dangerous and a resolved Dr. Reese (Rachel DiPillo) does her best to help. Elsewhere, Dr. Latham (guest star Ato Essandoh) makes a big admission to Dr. Rhodes (Colin Donnell) while Dr. Halstead (Nick Gehlfuss) must deal with a difficult case that is further complicated by Dr. Stohl (guest star Eddie Jemison), who has a camera crew following him around to shoot a promotional video spotlighting the hospital. S. Epatha Merkerson, Marlyne Barrett and Yaya DaCosta also star.