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.

The 126 race to rescue a woman with an arrow shot into her head; Judd is doubly surprised by news Wyatt shares; Mateo helps a family member in need and comes to regret it.

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.

Judd is shocked at the latest victim of an emergency call, Grace and Carlos must save a woman literally trapped in a domestic abuse situation and the 126 arrive at a horrific highway crash that threatens the lives of a father and daughter. Meanwhile, Owen and Gwyneth face a difficult decision in their relationship and Mateo regrets his new tattoo.

Owen and the 126 deal with the aftermath of the asteroid crash in Austin while an even greater threat looms.

The 126 is on the scene when a disastrous wedding comes crumbling down, as Grace helps a dominatrix and her slave involved in a shocking situation. Meanwhile, Owen and Gwyneth struggle to label their new relationship and a man from Marjan's past re-enters back in her life.

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.

Judd calls out Owen's preferential treatment of T.K.. Marjan feels ostracized at her new mosque after another rescue video goes viral. Owen helps Michelle uncover new information about her sister's disappearance.

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.

The members of the 126 spring into action when a surprise military homecoming erupts into chaos. Meanwhile, Owen is left responsible for taking care of a talkative pet, Paul faces a medical emergency and Tommy goes on her first date since Charles' passing.

Owen, Tommy & the 126 race to the rescue when a medieval-themed restaurant suffers a case of carbon monoxide poisoning. Meanwhile the crew is worried that Paul still has not mentally recovered from his surgery and his friendship with Marjan is over. Mateo is offered a promotion by his old fire captain, but quickly realizes he is not the man he once knew.

The members of the 126 race to find, and then save, a mystery victim in a car crash. Meanwhile, Owen faces a crisis in his relationship with Catherine. Tommy goes on a first date and Carlos is surprised when he meets T.K.'s AA sponsor.

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.

Tommy goes paramedic crew-to-crew against her former employer, private contractors Paragon Medics, as they deal with emergencies involving a dialysis patient and at a perfume factory. Meanwhile, Owen hits it off with a beautiful woman he meets at a fundraiser.

When she discovers her former fiancé is having a baby with his new wife, The 126 help Marjan enter the dating world through a series of chaperoned dates; Owen and the team are called to the rescue when a pregnant woman takes matters (and her anger) out at a motel where she suspects her husband is cheating on her.

The 126 race into action when a horse barrels into a brewery with an unconscious rider on its back and then to a bus full of tourists all experiencing seizures. Judd introduces Owen to Wyatt's mother Marlene. Carlos and T.K. start couples counseling, when Carlos investigation into his father's murder becomes all-consuming.

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; Grace tries to reconnect with Judd; Owen faces the consequences of his chemo.

The crew deal with a runaway bull at a used car lot and an apparent electrocution at the hands of an LA transplant; Michelle gets the strongest lead yet on her missing sister.

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 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.

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.

Captains Strand and Vega along with the members of the 126 are called into action to a county fair when a "Derecho," a series of fast-moving severe thunderstorms, hit Austin, causing hurricanic and tornadic-force winds, heavy rains, flash floods and a wide path of destruction. Owen's newfound passion for motorcycling puts him on a potentially dangerous path. Tommy has the potential for a romance when she meets an attractive single father. And as T.K. and Carlos prepare for their wedding, a secret from Carlos' past may stand in their way to happiness.

Captain Strand and the 126 race to the rescue when a woman is trapped in her mobile house that has been hijacked by her ex. Owen has a run in with former nemesis Sgt. O’Brien and is then questioned by the FBI. Tommy asks Grace dating advice. T.K. and Carlos meet with Iris Blake.