The BAU feels the heat when they head to the famous Santa Monica pier to investigate burned bodies left near there, and Rossi reconnects with his former Marine sergeant from Vietnam.
Dr. Lewis is confronted by a private physician concerning her risky treatment of a heart patient. Carol returns to work at the ER. A mysterious woman wanders the halls of the hospital.
Dr. Ross and Dr. Greene treat a 5-year-old girl who accidentally swallowed cocaine. Closed ERs at two other hospitals make the ER very busy. Susan's sister, Chloe, is becoming mentally unstable.
Jennifer informs Mark that she wants a divorce. Benton falls asleep while taking care of his mother, and she gets injured. Susan is fascinated by a doctor she meets--but the man is a fraud.
Benton asks Jeanie to inform her husband about their love affair. Carter is attracted to a new med student, Harper. Carol rides with paramedics for the day. Weaver antagonizes Lewis and Ross.