Dr. Halstead and Dr. Manning deal with two warring brothers who are brought together when one finds himself in desperate need of a kidney. Dr. Reese's former patient Danny comes to a crossroad. Dr. Rhodes and Dr. Latham treat a 16-year-old girl with a genetic condition in need of surgery, but whose overprotective mother disagrees with that course of action. A convict with unusual intentions puts himself in the hospital and Dr. Charles meddles in his daughter Robyn's personal life, much to her dismay. Meanwhile, Dr. Halstead and April make a discovery that complicates her treatment for TB.

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).

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.

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.

Caroline has news to share, forcing Dr. Charles to make a serious decision about their relationship. Maggie meets her sister's new boyfriend, but discovers danger may lie ahead. Dr. Rhodes experiences a devastating loss while Dr. Choi and April are faced with an unexpected challenge that strengthens their relationship.

Dr. Choi and Dr. Charles have difficult decisions to make as a dying man tries to preserve his life with a controversial scientific method. Dr. Marcel and April clash over how to handle a mysterious patient. Will questions Natalie’s capabilities.

April receives unfortunate news that makes her question her future with Ethan. Dr. Charles and Maggie see tough times on the horizon. Natalie’s memory from the accident starts to return.

Will runs into trouble when one of his trial patients falls ill. His own stress and symptoms have Ethan struggling to get through the day.

Stevie’s personal and professional worlds collide when her mother becomes her patient. Dylan’s history with the father of a patient interferes with his perception of a case. Crockett's allegiances are challenged when his patient's liver is a potential match for one of Dr. Blake's patients.

Charles and Cuevas clash over the treatment of a paranoid patient. Choi treats a pregnant patient from Asher's past. Marcel and Taylor help a man who needs a risky neurosurgery.