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. 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.