The grand opening of Chicago Med's emergency department is interrupted by victims of an elevated train crash, pushing the staff to their limits.

Dr. Rhodes must confront his past when he treats a close family friend who's been impaled by glass in a case that reunites him with his sister. Meanwhile, a musician must decide to undergo surgery that will save her life but could destroy her hearing.

The doctors treat victims of a movie-theater shooting as Sharon Goodwin tries to keep the press at bay. A teen with an eating disorder is treated, but Dr. Charles' methods rub others the wrong way. The staffers deal with a racist patient.

A member of Firehouse 51 clings to life and takes a sudden turn for the worse as medical staffers race to give treatment. Meanwhile, Dr. Natalie Manning prepares for her pregnancy and members of Chicago P.D. probe the case of a woman pulled from a fire.

The crossover starts on Chicago Fire S04E10 The Beating Heart (I). It continues on Chicago P.D. S03E10 Now I'm God (III).

Dr. Rhodes and Dr. Downey clash over how to treat a patient with various health and heart issues. Meanwhile, excessive hoarding at a home comes into play when trying to help a man with a leg injury; a patient is bitten by her own dog; and a commission pays a surprise visit to evaluate the hospital.

Dr. Manning and Jeff Clarke are forced to figure out a mystery illness when an Indonesian man who doesn't speak English arrives at the hospital in dire straights. Maggie takes Dr. Halstead to her family reunion. Dr. Rhodes takes on a complicated heart surgery without consulting Dr. Latham. Dr. Reese and Dr. Charles encounter a woman experiencing an unusual pregnancy.

Dr. Manning tends to a young cancer patient and struggles to inform the parents of her dire condition. Elsewhere, Dr. Reese gets contacted by Danny, the troubled young man, and turns to Dr. Charles and Det. Lindsay for help in resolving a difficult situation. Goodwin and Maggie do their best to clear the logjam in the hospital and Dr. Rhodes fine-tunes his instincts after both Dr. Latham and Dr. Halstead pick up on things he doesn't. Meanwhile, a teenage science geek and her friends impress Dr. Choi and Natalie with their bio-engineering lab.

Dr. Rhodes and Dr. Charles' heart transplant patient gets into a car crash, revealing issues that could complicate her surgery. A past arrest causes trouble for Maggie when the arresting officer is brought to Chicago Med with a serious injury. Elsewhere, Dr. Manning and Dr. Halstead must defend their actions when explaining a patient's cause of death. Meanwhile, Dr. Halstead attempts to treat an uncooperative horse jockey.

The doctors of Chicago Med take their opinions to the extreme as they try to bring justice to the perpetrator in the shooting of Dr. Charles. Dr. Halstead and Dr. Manning work on a heart-wrenching case that forces them to examine their own matters of the heart. Though Robin’s brain tumor was removed and she is discharged from the rehabilitation center, Dr. Rhodes remains on edge that her problems are not quite resolved. Meanwhile, Rhodes gets blindsided by his colleague Dr. Bekkar, Maggie sticks up for a patient and Dr. Choi and April try to navigate their new working relationship.

Bekker takes drastic action to keep Rhodes from leaving Med for good. Meanwhile, Halstead questions Manning's feelings about their upcoming wedding, Ethan receives shocking news about his sister, and Dr. Charles mourns a loss.

The doctors and nurses of Chicago Med find themselves on high alert when an overflow of patients are rushed into the doors following a terrifying apartment complex blaze. Dr. Rhodes fights to save the life of one of Chicago Fire's own, while Dr. Halstead and his brother Jay struggle with their own personal battle.

The crossover starts on Chicago Fire S07E02 Going to War (I). It continues on Chicago P.D. S06E02 Endings (III).

April finds herself in a dangerous situation and Natalie gets an update on Will. Dr. Rhodes gears up for a gala honoring his hybrid O.R. and tries to convince Dr. Bekker to join him.

Dr. Manning's actions with a recent patient lead to serious repercussions. April and Noah disagree over a patient who is injured after a beating. Dr. Charles is visited by a childhood friend with a surprising revelation.

The crossover starts on Chicago Fire S08E04 Infection (I). It continues on Chicago PD S07E04 Infection, Part III (III).

Dean and Ethan respond to a scene that brings back some bad memories. When Carol's condition worsens, Natalie is willing to do whatever it takes to get her mom feeling better.

In the aftermath of Halstead's apartment fire, Marcel, Choi and Archer work together to try to save the survivors. Charles and Med's new fellow, Cuevas, help a paranoid patient.