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

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.

On her way back to Austin, Marjan is in for the fight of her life when she is targeted by a killer.

Grace and Carlos work together when they suspect a young woman was a victim of a black market organ trafficking ring; Owen's brother Robert comes to visit and meet T.K., but surprises Owen with news that can affect the Strand family.

Owen is conflicted when his brother Robert asks him for help; Judd and Grace face a family crisis; As T.K. and Carlos prepare for their wedding day tragedy strikes.

The 126 race into action when a major train derailment causes multiple injuries; Meanwhile Tommy makes a bold move in her relationship with Trevor; Wyatt asks Owen to give Judd his job back as Marjan and Paul continue to compete for the open position.

A gang killing leads Carlos to new information on his father's murder. TK contemplates a major life decision as Owen is determined to get Austin's first responders' health care coverages increased.