The lives of men and women who work the night shift at a hospital in San Antonio come to life in this drama. In the premiere, a former military doctor (Eoin Macken) 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.
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.
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 (Scott Wolf) arrives.
A violent storm pummels San Antonio, sending numerous patients to the emergency room. Elsewhere, TC and Dr. Scott Clemmens (Scott Wolf) 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.
A horrific crash sends dozens of soldiers, including Drew's boyfriend, to the emergency room, where TC and Scott clash. Meanwhile, Topher tries to diagnose a soldier's illness, and Kenny tries to improve Ragosa's online-dating profile.
TC and Topher treat the lone survivor of a plane crash while fending off an intimidating law-enforcement officer with a secret motive. Meanwhile, Paul is smitten by an injured exotic dancer whose condition takes a turn for the worse; and Krista cares for a teen with an eating disorder.
A shoot-out in the ER leaves Topher seriously wounded. Elsewhere, TC tries to control his Afghanistan flashbacks; an explosion at a fertilizer factory sends burn victims to the ER, overwhelming the shorthanded staff; and Jordan discovers a secret about TC.