Will is troubled with a moral decision when his former teacher, Dr. Bella Rowan, is faced with a life-threating disease. Dr. Rhodes and Dr. Bardovi get involved in a sensitive situation when Rhodes disagrees with the father of a young patient regarding a risky procedure. Dr. Charles and Sarah handle an unusual case with a pilot that causes Sarah to have memories of Jason Wheeler's suicide. Maggie takes an aggressive approach to training a new nurse.

Halstead hides the theft of his gun from a suspicious Manning. Tensions are still high between Connor and Bekker, who take a risk operating on an HIV-positive patient. Hank breaks down when he sees a patient from his past.

Will and Natalie battle for their lives after a car accident. An investigation is launched following the suspicious death of Cornelius Rhodes. Maggie receives life-changing news. Dr. Charles cuts his honeymoon short to tend to a patient.

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).

The staff adjusts to the new normal of the pandemic. Dr. Choi, Dr. Lanik and April fight on the front lines. Dr. Halstead and Hannah face a troubling reality. Dr. Charles tries to clear the air with his daughter following recent developments.

Carol receives a second chance at life when a new heart becomes available. Ethan and Dean find themselves in hot water with an old patient. Will faces the consequences of the stolen trial medication.

In the aftermath of the Vas-COM scandal, Goodwin clashes with the hospital’s new compliance officer. Crockett and Blake try to save a patient who has a son with severe autism. A patient’s son lies to his father about his diagnosis.

Dylan and Ethan treat a patient shot during a drug raid. Charles and Vanessa work together to properly diagnose a motivational speaker. Will and Hannah must turn to Crockett for help with a patient who's pregnant.

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.