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 (guest star Lisa Edelstein), and receives an update on his cancer. 
This is the first episode to not feature Michelle Blake, with Tommy becoming her replacement.
It is revealed a little while after the events of the previous episode, she stepped down from her position to focus all of her time and energy on helping mentally ill people living on the street.
Tommy mentions that the last tine she was up high in a harness, the show Gilmore Girls was still on the air, which ran from 2000 to 2007.
The tank rampage scene is similar to the rampage Shawn Nelson went on in May 1995, when he stole a M60A3 Patton tank from a U.S. National Guard armory in San Diego, only that he was shot and killed at the end.
Owen's cancer which was previously diagnosed in "Pilot", has now gone into the process of remission.
9-1-1- Lone Star Season 2 First Look Preview (HD) Rob Lowe, Gina Torres 9-1-1 Spinoff
Vega & Her Husband Have A Heart-To-Heart - Season 2 Ep. 1 - 9-1-1- LONE STAR
Captain Strand Shows Captain Vega Her New Office - Season 2 Ep. 1 - 9-1-1- LONE STAR
T.K. Gets Stuck In The Middle Of A Parental Argument - Season 2 Ep. 1 - 9-1-1- LONE STAR
Owen & Tommy Rescue A Man From A Cell Tower - Season 2 Ep. 1 - 9-1-1- LONE STAR