The doctors of Chicago Med experience various changes.

Dr. Choi mentors a Navy corpsman, while two cases involving sick babies may have a connection.

Family secrets are revealed when Maggie's sister visits.

Dr. Charles' daughter deals with cases of a rare infection when she joins the epidemiology department.

An accident at the Chicago Marathon puts the medical personnel into action.

Sharon's childhood sweetheart arrives at the hospital, while Halstead tries to get his finances in order.

April discovers her TB medication may lead to further problems, while Dr. Choi learns an important lesson as he treats two MMA fighters who are in bad shape.

Maggie faces her past when the police officer who arrested her is brought into Chicago Med with a serious injury.

Dr. Reese endures a long night on the graveyard shift, while Dr, Rhodes is asked to work on a most unusual patient.

Dr. Latham is talked into going with Dr. Rhodes on a medical trip out of town; an 8-year-old cancer patient wants to give up; a woman with a personality disorder makes a case complicated.

The doctors and nurses of Chicago Med brace for an influx of patients when a multi-vehicle accident during a blizzard puts the hospital in scramble mode.

Dr. Rhodes is under pressure to keep a trauma patient alive and April befriends a patient with a failing heart.

Dr. Manning deals with treating a comatose young woman who's pregnant.

Choi and Halstead argue over how to treat a patient with stroke symptoms while Manning treats a boy who fell in the river and watches the family drama unfold.

Will's former teacher has a life-threatening disease while Rhodes argues with the father of a young patient over a risky procedure.

The hospital computer system is shut down by a hacker demanding a ransom payment.

The doctors deal with trying family matters.

Rhodes tries to save a mother who's determined to help her daughter beat cancer.

Dr. Rhodes clashes with Dr. Charles and other medical staff over how to treat Dr. Charles's daughter Robin.

Robin returns to the hospital with more complications; Rhodes faces competition from a new doctor.