As a wildfire spreads across Texas, Evan "Buck" Buckley, Henrietta "Hen" Wilson and Eddie Diaz from the 118 firehouse in Los Angeles arrive in Austin to help Capt. Strand and the 126. As the crews race to save a group of teenagers trapped by the fire at a campground, Owen and Hen fight for their lives in the aftermath of a helicopter crash.

Facing his anger management issues, Owen has a breakthrough in therapy. Then, after a particularly devastating emergency call, Grace reaches out to a co-worker, but regrets when Judd offers more than she was planning. Also, a clown has an emergency at a young boy's birthday party, and Tommy, T.K. and Nancy race to help a survivalist who has a painful encounter with a reptile.

Captain Strand and the 126 come together when one of their own is trapped after a building explosion. Meanwhile, Owen reflects on his 9/11 experience, T.K. and Carlos come to a decision and Tommy and Julius decide on their future.

A bank robbery, an apartment fire and a pregnant woman lost in a parking garage are the seemingly unconnected calls to which the 126 responds. Then, T.K. celebrates his one-year anniversary of sobriety, while Owen and Gwyn may not make it to the end of the week as a couple. Also, Carlos finds himself working on a case with his Texas Ranger father.

Grace and Judd fight for their lives in the aftermath of the horrific car accident, as flashbacks show how a childhood tragedy led Judd to meet Grace and how they ultimately fell in love.

The 126 make calls to a bloody disaster at an ice cream shop and help rescue a boy missing from his own birthday party. Meanwhile, the 126 holds an "intervention" for Owen after he accidentally spills his secrets to new roommate Mateo. Then, T.K. and Carlos take a big step in their relationship, as Grace learns to rely on others in the aftermath of the car accident.

After being forced to take time off work to recover from his surgery, Owen finds himself immersed in the search for a serial arsonist. Meanwhile, T.K. and Carlos take their relationship to the next level and Marjan copes with the aftermath of losing someone on the job.

Owen and the members of the 126 race into action when a massive dust storm engulfs Austin. Season finale

An unexpected arctic cold front brings an ice storm to Austin and a variety of weather-related emergencies. Meanwhile, Owen deals with the fallout of the 126 closing, as Tommy, T.K. and Gillian settle into new employment, and Judd and Grace prepare for the birth of their first baby.

As the unexpected arctic cold front and ice storm continues to cause havoc in Austin, Owen works to rescue the lives of the stranded migrants; T.K.'s life hangs in the balance and Grace prepares for the birth of her baby.

Owen's first date with the beautiful and accomplished Chief of Staff to the governor of Texas goes awry. Meanwhile, the members of the 126 arrive at a house fire and find a couple's young daughter is missing. Then, Judd meets a teenager who has a profound impact on him.

Owen and the 126 race to the rescue when Catherine receives a package at the governor's office that may contain a bio-hazard. Meanwhile Grace and Carlos team up to investigate a prank 9-1-1 call that turns deadly.

The 126 respond to emergencies when a man falls into a trash compactor and a frantic mom tries to rescue her kids in a runaway car. Meanwhile, Tommy and Julius grow closer, as two team members disagree on keeping their romance a secret.

Owen helps Tommy through a personal emergency.

Grace is caught in the ice storm as she goes into labor, and Judd, Owen and Tommy race to find her.

In an attempt to bond with Wyatt, Owen and Judd take the teen alien hunting, but their search takes a different turn when they find two dead bodies. Meanwhile, Tommy joins a grief group for widowers, as mysterious events around her house lead her to believe Charles is communicating from the beyond with her and the twins. Then, a woman fears she is cursed and takes drastic measures to cure herself.

Owen is conflicted when his brother Robert asks him for help; Judd and Grace face a family crisis; As T.K. and Carlos prepare for their wedding day tragedy strikes.

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

The crew race to a rattlesnake infestation, and attempt to rescue a man with dementia from a dangerous scene he created; Michelle learns the truth behind her sister's disappearance; A tragic accident shakes the crew 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. Meanwhile, Owen helps T.K. reconcile the past to help his future, Judd and Grace aid Judd's aging father.

Owen helps T.K. reconcile the past to help his future; Michelle learns the full truth about Iris.

Owen and T.K. risk their lives to save two brothers trapped in a homemade minefield. Meanwhile, Grace receives an emergency call from a conjoined twin who's brother is dying, Tommy interviews new candidates to fill the team's open EMT position and Paul's mother and estranged sister pay him an unexpected visit.

The 126 arrive at a funeral where another dead body has crashed the burial, and then to a hospital where an MRI has gone haywire. Owen and Tommy each feel displaced in their homes as Gwyn moves into the Strand household and Charles seemingly becomes the full-time parent in the Vegas'. Meanwhile, T.K. makes waves in his new position.

When T.K.'s mother, Gwyn, has an emergency, Owen and T.K. travel to New York. But the flight is anything but smooth when the plane experiences a mechanical failure. Meanwhile T.K. reflects back when Gwyn helped get him into rehab years ago.

Owen and the 126 race to emergencies at a fast food drive-thru, a high school wrestling match and a case of road rage - all with one common element tying them together. Meanwhile, Tommy's estranged brother-in-law makes a surprise appearance in Austin, and Marjan confronts Capt. Strand about his anger management issues.