The crew races to an outbreak of mercury poisoning leaving its victims in a zombie-like state; Owen must come to terms with his illness; Michelle follows a new lead on her missing sister.

Emergencies include an accident at a grain silo and a steak eating contest; Owen helps Michelle uncover new information about her sister's disappearance.

A massive tornado sweeps through Austin, as the crew races to save those in its path.

The crew races to a brawl at a male strip club, a fire at a bull semen factory and a protest; Grace tries to reconnect with Judd; Owen faces the consequences of his chemo.

Emergencies include a ride-share trip gone awry, a farming accident and a memorial service that may turn into another funeral; Owen unexpectedly bonds with the former Captain of the 126; The crew help Mateo with his written exams.

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.

The crew race to a rattlesnake infestation, and attempt to rescue a man with dementia from a dangerous scene he created; Michelle learns the truth behind her sister's disappearance; A tragic accident shakes the crew to its core.

The crew race to a gender reveal party gone horribly wrong, and a father/son trapped in a cave during a spelunking excursion; Judd and Grace aid Judd's aging father.

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