Owen Strand, the lone survivor of his Manhattan firehouse on 9/11, takes his progressive philosophies of life and firefighting down to Austin, Texas, where he helps the firefighters of Firehouse 126 start anew.

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.

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

The 126 crew responds to a military tank on the loose in downtown Austin and a human pile-up at the roller derby. Meanwhile, new paramedic captain, Tommy Vega, joins the team and Owen is reunited with his ex-wife and T.K.'s mother, Gwyneth, and receives an update on his cancer.

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.

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