When a dust-up between Owen and an obnoxious police sergeant goes viral, the existing tensions between police and fire rescue mount, leading Owen to decide they will settle the score on the softball field. Meanwhile, Grace competes against a hot shot call center night-shift operator when he moves over to the day shift.

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.

As Owen gets pulled deeper into the FBI’s investigation of the motorcycle gang, Sgt. O’Brien makes a confession to him. Meanwhile, Grace and the 126 respond to a call from a man who claims his girlfriend slipped over the side of a cliff and Carlos searches for a missing friend, putting his own life in danger.

As Owen wears an FBI wire for his meeting with O'Brien, The Honor Dogs crash the meet-up and let them know there's an infiltrator in their midst. A frantic TK desperately searches for a missing and held captive Carlos.

Capt. Strand reveals to the 126 he has been working with the FBI to help bring down a domestic terrorist group with his Austin motorcycle club/gang The Honor Dogs, then race Owen to respond to a bomb threat at the State Capitol and put a stop to the terrorist deadly plans.

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.