Rhodes and Bekker put it all on the line to safely separate conjoined twins; Choi and Manning treat a disease outbreak at a homeless encampment; Charles confronts Reese's father.

Rhodes makes a risky decision to try to save a pregnant woman and her unborn child; despite the tension between them, Manning and Halstead team up to treat a flu victim.

Chaos rips through Med when a mass shooting floods the ED with victims, and the staff must go into overdrive to control the mayhem, comfort the heartbroken and save as many lives as possible.

Reese's father has days to live, and she is conflicted about saying goodbye to him; Bekker delights in Rhodes' jealousy when she receives flowers from another man.

Sharon's teenage godson comes to the ED with burns from a house fire; Manning and Charles must tell a mother that her daughter is genetically male.

The lives of conjoined twins hang in the balance when one twin suffers heart failure; when an exorcism goes wrong, a possessed woman ends up in the ED.