The team pursues a copycat serial killer who is recreating the techniques used by past famous murderers.
Dr. David Morgenstern (WILLIAM H. MACY) takes a trip down memory lane as he stops by County General and Sam's sister (SHANNON WOODWARD) pays an unexpected visit.
Banfield and her husband look into adoption, while Carter adjusts to a changed ER. Sam's mother (guest star AMY MADIGAN) comes into the ER in an altered state of mind.
Hal and Lois take the family on a houseboat vacation with the Kenarbins.
Topics include President Donald Trump's reaction to criticisms of rescue efforts for Puerto Rico after Hurricane Maria, the most recent iteration of the health care bill, tax reform and forensic science.