Dr. Charles and April team up to take on a mysterious patient in the ED. Dr. Halstead is forced to make a life-or-death decision for one of his trial patients. Dr. Marcel is confronted by his past when a former acquaintance is brought into the ED.

Cast: Nick Gehlfuss, Yaya DaCosta, Torrey DeVitto, Brian Tee, Dominic Rains, Marlyne Barrett, S. Epatha Merkerson, Oliver Platt, Nate Santana, Tehmina Sunny