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, Tommy, T.K. and Gillian race to rescue a young boy who has fallen in a frozen pond. Judd and Mateo work furiously to help a trapped Paul, and Owen takes drastic measures to save a man who has been stabbed and left for dead.

Owen fears the past is back to haunt him when a stalker targets him and Catherine. Meanwhile, Tommy and Gillian face consequences when Gillian saves the life of a woman wearing a "Do Not Resuscitate" bracelet.

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.

The 126 race to contain a toxic chlorine cloud of death unleashed by the train derailment. Owen names the station's new lieutenant as Judd finds a path forward.