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.

Dr. Charles is forced to make a decision about his relationship with Caroline; Maggie meets her sister's new boyfriend; Dr. Rhodes experiences a huge loss; Dr. Choi and April face a challenge.

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.

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

Dr. Rhodes receives an alarming phone call that prompts him to rush out in the middle of an important surgery; Halstead comes to the aid of an FBI agent who is brought into the ED.

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