A New York firefighter relocates to Austin, Texas with his son, where he works to save people's lives while trying to solve his own personal problems.
Cast: Rob Lowe, Liv Tyler, Ronen Rubinstein, Sierra Aylina McClain, Jim Parrack, Natacha Karam, Brian Michael Smith, Rafael Silva, Julian Works, Mark Elias
Owen and the 126 deal with the aftermath of the asteroid crash in Austin while an even greater threat looms.
Owen makes a decision about his future. Tommy receives devastating news. T.K. and Carlos worry about adopting Jonah. Mateo gets his immigration status threatened after an altercation. A doomsday prepper gets trapped in a bomb shelter and The 126 and all of Austin brace for an asteroid crash.
Judd literally walks into the line of fire when an armory catches on fire, sending bullets flying everywhere. Owen questions Judd's pledge of sobriety. Marjan introduces boyfriend Joe to her parents, Waleed and Nasreen, but their dinner doesn't go as smoothly as she hoped.
Carlos is determined to solve his father's murder. Owen is offered a life-changing opportunity. Judd gives into his demons. Tommy begins her treatment.
A gang killing leads Carlos to new information on his father's murder. TK contemplates a major life decision as Owen is determined to get Austin's first responders' health care coverages increased.
T.K. gets a huge surprise on his 30th birthday when his stepdad and young half-brother arrive in Austin. Tommy is determined to push through her latest crisis. The 126 must perform a dangerous surgery after a man is impaled in a tree.
The 126 race to save a man crushed under a vending machine. Owen finally faces the truth of his brother's death. Mateo and Nancy scramble to delete a nude photo of her accidentally sent to the 126.
A horse barrels into a brewery with an unconscious rider on its back; a bus full of tourists all experience seizures; Judd introduces Owen to Wyatt's mother; Carlos investigation into his father's murder becomes all-consuming.
The 126 are called on the scene to a hoarder's rat-infested house, then are trapped in an elevator as a woman goes into labor. Tommy and Trevor host his ex-wife Cassandra for dinner which goes awry.
The 126 race to contain a toxic chlorine cloud of death unleashed by the train derailment. Owen names the station's new lieutenant. Judd finds a path forward.
The 126 race into action when a major train derailment causes multiple injuries. Tommy makes a bold move in her relationship with Trevor. Marjan and Paul continue to compete for the open position.
The 126 race into action when an armored truck and its guards are attacked by a group of masked men; Owen attends group therapy with Tommy to deal with his brother Robert's death; Marjan and Paul each apply for the open lieutenant position.