Lorena Diaz

An airfield emergency triggers a deeper mystery involving a passenger plane, propelling the Intelligence Unit into a high-stakes pursuit of the culprit, all under the sharp eye of the FBI.

Ethan finds himself at odds with Natalie and Sharon when it comes to the treatment of a troubled teenager who's just given birth; Dr. Halstead treats a hypochondriac with an overbearing wife.

Rhodes and Zanetti race to save a member of Firehouse 51; April's brother struggles during his first day at the hospital; a woman saved from a burning building leads to a bigger mystery.

Dr. Rhodes begins his cardiothoracic surgery fellowship but gets off on the wrong foot with his new boss; Dr. Choi begins his life as chief resident; Sarah is caught off-guard by Dr. Charles; April tries to deal with her recently discovered illness.

Dr. Choi is tested when an erratic patient takes drastic measures; Dr. Manning questions the circumstances behind a young boy's broken wrist.

Dr. Halstead's career is in jeopardy when he revives a terminally ill patient, despite an order to not resuscitate; a patient inspires Dr. Choi to seek advice from Dr. Charles; everyone is shocked by a revelation about a member of the staff.