Goodwin clashes with new hospital COO Gwen Garrett while April questions whether Ethan's sister is using drugs again; Charles confronts his past actions.

An overflow of patients is rushed into Chicago Med following an apartment blaze and Rhodes tries to save a firefighter's life, while the two Halstead brothers face their own personal battle.

A sick boy is brought to the hospital, forcing Ethan to face a tough decision that grows into a complicated and dangerous situation.

The CPD pays Dr. Halstead an unexpected visit; Ethan is skeptical of a woman experiencing chronic pain; Natalie takes care of a cancer patient whose brother refuses to help.

Will must lie to Natalie; Ethan and April uncover compromising information about Emily's boyfriend; Ava isn't sure what to do with a patient who doesn't want treatment.

Manning and Halstead work quickly to save a physically abused wife; Choi and April discover a shocking truth about a 14-year-old cirrhosis patient; Rhodes and Lanik face off in the ER.

The ED goes on lock-down due to a deadly chemical spill that threatens the lives of patients and leaves one of Med's own in the balance; Rhodes and Manning attempt to perform live-saving surgeries.

Dr. Charles and Dr. Choi are at odds over surgery. Dr. Rhodes finds himself in hot water.

Will and Natalie prepare for their big day, but an unsuspecting Will soon finds himself sidetracked.

Halstead takes heat for making an unauthorized move to treat his pregnant patient. Choi becomes personally invested when treating a homeless veteran. Rhodes and Bekker deal with a patient who desperately needs a liver transplant.

Dr. Halstead rushes to rescue Dr. Manning from a chopper crash. Drama between Dr. Rhodes and Dr. Bekker boils over. Dr. Charles and Dr. Choi work to help a patient with their addiction. April helps Elsa deal with losing her first patient.

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.

Connor, who is in hot water with the hospital's Oversight Committee, handles a gunshot victim with unexpected ties to Halstead. Maggie feels guilty about the return of a former patient. Charles has an awkward first date.

Natalie and Maggie witness a pickup truck plow through a street fair and must make tough decisions on the fly. At the hospital, doctors and nurses are on high alert with the influx of patients. Dr. Charles' ex-wife comes to town with news.

Halstead treats a woman on the verge of freezing to death. Dr. Charles' ex-wife receives some concerning news. Choi handles a lymphoma patient with viral meningitis and a complicated family. Manning makes a house call.

When a car unexpectedly smashes through the ambulance bay doors, Dr. Choi makes some difficult decisions in an effort to save a worker trapped beneath the wreckage and April, who's also in danger.

The hospital goes into lockdown mode when a man with a gun holds medical staff hostage. Goodwin is forced to make a tough decision. Dr. Rhodes begins to realize his time with his father is getting short.

Dr. Charles and Caroline set some major plans; Ava fights to keep her relationship with Connor. Agent Lee informs Will of news that may put his life in danger.