The overnight crew becomes immersed in a bizarre car-accident rescue. Drew serves overseas in Afghanistan and teams with a colleague to treat an Afghani woman, A spunky grad joins the shift.

TC and Scott fight to save a boy and his mother who were injured in a car accident, yet it becomes clear there's more to the family dynamic than meets the eye. Deployed in Afghanistan, Drew and Syd face the aftermath of an OR shooting.

Drew stressfully adjusts after returning from deployment in Afghanistan. A bride and her wedding party are treated for injuries sustained during the festivities, and Topher's demanding mother pays a visit.

As the city erupts in violence over an impending jury verdict, the night shift becomes ground zero when they have to take in the man suspected of the racially-motivated shooting at the source of the unrest. His presence in the emergency room sparks sharp conversation and disagreements among the staff over the highly-charged topic and even close friends Kenny and Paul find themselves at odds. Topher does his best to control the mounting chaos in the ER while out in the field, TC makes a decision as to which of two patients to bring in, leaving Paul and Scott to question TC's motives.

A college co-ed falls from a balcony and once she is in the ER, TC and Paul find that her situation is even more complex. Jordan bonds with a terminal patient who teaches her some important lessons about living. TC's errant sister-in-law Annie returns and hopes to make amends. Meanwhile, Jessica - a pharmaceutical rep with cutting-edge equipment that Scott is so close to getting for the hospital - if her tension with TC doesn't kill the deal.

Shannon and Jordan venture out for some fun at a local wrestling event only to find themselves treating people on site when a fight breaks out amongst the audience. Back at the hospital, Sam attends to a marathon runner who has collapsed from the heat and things start to heat up even more when the air conditioning breaks. Meanwhile, tensions between TC, Jordan, Sam, and Annie start to boil.

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.

The doctors race to save Topher's mom when she comes to the ER with life-threatening symptoms. The team discovers a gravely injured foster mom is harboring a secret. Jordan asks T.C.'s girlfriend for help with a patient.

When a bomb explodes outside the hospital, TC, Topher and Drew are forced to make the tough decision to stay and treat the injured or evacuate and begin transfers to nearby hospitals. Everything changes when TC suddenly realizes he may know the person responsible for the explosion. While the team works feverishly to tend to the wounded, the nurses go on strike just when the hospital needs them the most. Meanwhile, throughout the intense night shift, Shannon and Paul attempt to confront each other about something personal.

TC and Paul pull out all the stops when a crane collapses on a worker at a busy construction site. As Paul works tirelessness to save the crush victim, an observer falls into a deadly gravel pit. TC throws himself into the pit and races to save the patient before he's swallowed by the shifting gravel. Back at the ER, Scott is shaken as the teenage boy he paralyzed returns to the hospital with new complications. Jordan lends support as the emotional case exposes complicated feelings from the past. Meanwhile when a life-saving donor matches with cystic fibrosis patient, Brianna, Drew determines the depth of his feelings for her.

TC initiates a bar brawl, landing him and Drew in jail for the night. While behind bars, Drew and TC's relationship reaches a breaking point. Jordan rushes her date to the ER, where she's shocked to learn he's not who she thought he was. Topher fights for a patient who many doctors have dismissed. Scott and Annie struggle to save their relationship while Jessica works to win back TC's trust. Meanwhile, Syd meets Brianna, and Rick visits the hospital.

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.

Scott and Jordan must perform surgery in the field as the burning wildfire gains intensity around them. Syd has caught Typhus along with hundreds of other patients on the Syria-Turkey border, and TC goes to great lengths to get the medication. Meanwhile, Drew and Rick fight to keep Brianna, while San Antonio Memorial finds an unlikely buyer, though saving the hospital comes at a cost.

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.

After performing a daring on-site rescue to save a teenage girl, Drew is forced to re-evaluate his priorities as a new father. Back at the hospital, the ER is flooded with mass casualty victims from an amusement park disaster. Hoping to get Paul back on staff, Jordan facilitates a rapprochement between Paul and his father. Meanwhile, Scott pursues a more active role in the hospital and Kenny tries to put Cain in his place.

Jordan and Cain figure out their professional dynamic as they work on a patient with extreme injuries from an oil field explosion. Drew and Paul receive a patient from the same accident, and must figure out a solution to save the patient's severed hand. Scott is caught off guard when Annie shows up to the hospital with an unexpected guest from his past. Kenny and Shannon struggle to adjust to their new living situation. Meanwhile, TC and Amira clash over treating a Syrian child on the American base.

When a patient from a distant town journeys to SAM for surgery, Scott commits to helping her against all odds. Jordan and Cain help a wounded veteran come to terms with a diagnosis he doesn't believe he has. Meanwhile, Drew struggles with the exhaustion of being a working parent and finds support from an unusual patient. After a long night, Kenny learns life is too short to worry about trivial matters. TC joins a daring rescue mission in Syria.

Drew, his mom, and Rick's flight home turns into a medical crisis at 35,000 feet when passengers become sickened one by one. Jordan, Paul, Shannon, Kenny, and Cain spend their day off at an obstacle course fundraiser for Cystic Fibrosis, hosted by Akbar Gbajabjamila. Scott finds himself on a Tinder date he won't soon forget. Meanwhile, TC puts his own life in danger to operate on a soldier.

Kenny joins Drew at his MMA veteran's support group and finds himself in the fight of his life. Jordan and Cain treat casualties from a hotel fire while Shannon follows a hunch to help save a young victim. Paul's superstar sister, Dr. Bella Cummings, pays a visit to San Antonio Memorial. Meanwhile, TC finally returns home, forcing him to deal with Topher's death.

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.

When Jordan realizes the hospital is under cyber-attack, she leads the team in managing patient care as chaos ensues. Drew and Kenny treat a critical patient forcing Drew to call on his medical and military training. TC joins Rick and his partner on a SWAT drug raid. Meanwhile, he wrestles with whether or not he should return to Syria to tie up loose ends.

TC and Jordan accompany a SWAT team on a raid and wind up with an emergency room full of sickened immigrants, including one with murderous intentions. Scott pulls a dream team together to impress the Colonel in charge of setting up a combat training program. More is learned about Cain's past. Kenny shares some big news with the group, while Shannon keeps something personal from Paul.

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.