Dr. Halstead gets an unplanned visit from the CPD while Ethan is skeptical of a woman who is experiencing chronic pain. Natalie tends to a cancer patient whose brother has strong feelings on why he is refusing to lend his assistance

When things become complicated, Will is forced to lie to Natalie. Ethan and April find out some compromising information about Emily's boyfriend and Ava is unsure of what to do with a patient who is refusing treatment.

Dr. Manning and Dr. Halstead become skeptical of a patient's injuries when the victim of a car accident is brought into the hospital. Ethan and April have a difficult time understanding Emily's attachment to her boyfriend despite recent developments. Will and Natalie brace for their joint bachelor/bachelorette party.

The hospital is forced to evacuate when a toxic chemical is brought into the E.D., leaving patients and the staff in grave danger. Stuck in an elevator, Dr. Charles and Dr. Manning are forced to take drastic measures with a pregnant woman. Goodwin is tasked with making difficult choices and Dr. Rhodes discovers a secret that Dr. Bekker has been holding from him.

Dr. Charles and Dr. Manning disagree on how to handle a patient who they discover is poisoning herself. Dr. Rhodes throws some serious accusations at Dr. Bekker. Dr. Halstead has suspicions about Natalie’s new boyfriend and Dr. Choi tends to Bernie.

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.