Nearly 20 years ago, Owen Strand was the lone survivor of his Manhattan firehouse on 9/11. In the wake of the attack, Owen had the unenviable task of rebuilding his station. After a similar tragedy happens to a firehouse in Austin, Owen, along with his troubled firefighter son, T.K., takes his progressive philosophies of life and firefighting down to Texas, where he helps them start anew. On the surface, Owen is all about big-city style and swagger, but underneath he struggles with a secret he hides from the world - one that could very well end his life. Once in Austin, Owen meets the brilliant and wry chief paramedic Michelle Blake, as well as police officer Carlos Reyes. He then begins to assemble his new team of diverse and qualified candidates for Firehouse 126.

The crew races to a disaster at a wave pool, and an outbreak of mercury poisoning that is leaving its victims in a a zombie-like state. Meanwhile, Owen must come to terms with his illness and what the side-effects of treatment may do to his vanity. Also, Michelle follows a new lead on her missing sister while TK is unsure how to handle his budding relationship with Carlos.

Emergencies include an accident at a grain silo and a steak eating contest, plus an unusual home intruder. Meanwhile, Judd calls out Owen's' preferential treatment of TK. Also, Marjan feels ostracized at her new mosque after another rescue video goes viral. Then, Owen helps Michelle uncover new information about her sister's disappearance.

A massive tornado sweeps through Austin, as Owen, Michelle and their teams races to save those in its path.

Owen and the crew race to a brawl at a male strip club, a fire at a bull semen factory and a protest where male toxicity is taken to a new level. Meanwhile, Paul tentatively goes out on a first date, Grace tries to reconnect with Judd and Owen faces the consequences of his chemo.

Emergencies include a ride-share trip gone awry, a farming accident and a memorial service that may turn into another funeral. Owen unexpectedly bonds with the former Captain of the 126, while Marjan and the crew help Mateo try to pass his written exams.

Owen and the team race to deal with a runaway bull at a used car lot and an apparent electrocution at the hands of an LA transplant. Meanwhile, Owen is determined to prove he is physically fit for the job while undergoing chemo and Michelle gets the strongest lead yet on her missing sister.

Owen, Michelle and the 126 crew race to a rattlesnake infestation at a young family's home, and attempt to rescue a man with dementia from a dangerous scene that he created. Meanwhile, Owen adopts a firehouse dog with cancer and Michelle finally learns the truth behind her sister's disappearance. Also, a tragic accident shakes the team to its core.

Owen and the 126 crew race to a gender reveal party gone horribly wrong, and a father/son trapped in a cave during a spelunking excursion.

Owen helps T.K. reconcile the past to help his future, Judd and Grace aid Judd's aging father and Michelle learns the full truth about her missing sister, Iris.