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.

In the premiere, a former military doctor deals with a life-threatening situation on his way to work; his ex-girlfriend pursues the night shift's top job; and a clash over business matters unfolds.

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 desperately tries to save his critically injured friend. Meanwhile, Paul tackles a challenging case involving an elderly woman; Kenny helps an injured groom with a secret; and a 9-year-old boy has suspicious injuries.

TC and Paul race to the chaotic scene of an after-dark hog-hunting event that has gone nightmarishly wrong. Meanwhile, a 9-year-old girl arrives for treatment in a case that turns complicated; Drew injures his hand; and Ragosa seeks family counseling.

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.

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.

Injuries at an Alamo reenactment test the staff. Meanwhile, a disoriented patient suffering from amnesia receives care; Drew helps a severely wounded soldier; Topher schedules a vasectomy operation; and Jordan's boyfriend arrives.

An injured skydiver is rescued, but there's more to the case than meets the eye. Meanwhile, the night-shift staffers treat an electrocuted janitor, then scramble to save his wife and children when they fall ill to life-threatening symptoms; and Paul learns about his limitations as a doctor.

A patient arrives with radiation poisoning, spinning the night shift into chaos and putting it into lockdown. Meanwhile, staffers speed to a serious car crash, where they discover an injured police officer, TC's troubled sister-in-law visits, and a former patient harasses Jordan.

As a thick fog descends upon San Antonio, the doctors must improvise to save the victims of a car crash; Topher, Drew and Kenny treat siblings injured in the fog.

T.C. discovers his sister-in-law's complicated history after he treats her for a fall down stairs.

A building collapses during a rodeo; a severely injured cowboy exhibits strange symptoms; Scott causes a serious car accident.

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.

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.

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.

Topher takes over as chief of the night shift. TC is temporarily suspended. Jordan is scrutinized for her mishandling of the man who shot a recovered Topher. A father is trapped under an elevator. Ragosa returns to the ER.

The night shift is tested when a rancher accidentally shoots his wife. TC heads to a teen party to save the life of a young football star. Jordan and Kenny treat a beauty queen in severe distress. Topher makes a decision about his job.

A downtown gas explosion sends dozens of casualties to San Antonio Memorial Hospital.

Jordan and Krista offer roadside assistance to a motorcycle crash victim.

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.

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 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.

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.

A violent storm pummels San Antonio, sending numerous patients to the emergency room. Elsewhere, TC and Dr. Scott Clemmens rush to a mudslide disaster to treat a mother and her son; and Topher braves the storm to help his stranded wife, who's going into labor with twins.