A fireworks explosion creates chaos at a concert, sending patients streaming into the hospital as TC and Topher race to the scene. Syd returns from Afghanistan and faces her unique family dynamic. Jordan and Scott address simmering differences.

In part one of this two-part season finale, Scott and Jordan face grave danger during a rescue mission at a rapidly spreading wildfire outside San Antonio. Tensions are high between Syd and TC as they find themselves in the middle of a humanitarian crisis on the Syria-Turkey border. Paul and Shannon argue over treatment for a patient. Meanwhile a major setback threatens Drew's adoption plans for Brianna, Topher struggles to find a buyer for the hospital and medication goes missing.

Jordan and Drew perform a daring rescue by jumping from a chopper. Landing at the nearest VA hospital, Jordan sparks a plan to appease Julian and reunite her night shift team. Back at the hospital, Paul deals with the repercussions of standing up to his father while Scott dives headlong into his professional life. Kenny butts heads with Cain, a traveling nurse with a mysterious past. Shannon indoctrinates Cain as they work in San Antonio Memorial's understaffed and overworked ER. Meanwhile, TC is held captive in Syria. In order to find Syd, TC must treat his captor instead of returning to the safety of an air base with a civilian volunteer, Amira.

When protestors descend on a funeral for a dear member of the night shift family, multiple veterans are injured and brought to San Antonio Memorial for treatment. A high profile politician from Drew's past triggers flashbacks to his time in Iraq. Jordan, Scott, and TC disagree on how to best provide care for the politician. Paul and Shannon must improvise while tending to Doug, a former POW. Cain and Drew treat a fearless photographer.

A shooting at a nearby college sends TC, Jordan, Drew and Amira into the field, where they assist Rick with a deadly situation. Scott implements a new training program and locks horns with Julian. Drew struggles with frustrations about going to Army Ranger School while Shannon and TC both contemplate their future at San Antonio Memorial.