Hondo has a tense reunion with a fellow Marine, Ruiz, when the team hunts an escaped convict who was broken out of prison by criminals using stolen military weapons; Chris prepares for a difficult goodbye when her former K-9 partner becomes ill.

The SWAT team’s search for an abducted teen leads them to a member of the Witness Protection Program and a decades-old political extremist group. Also, Hondo and his girlfriend disagree over a guest speaker at her community center; Luca worries he’s not physically ready to return to the field; and Commander Hicks reconnects with his estranged son.

As the team works to stop a violent attack on the city, they're forced to confront the group responsible for the death of a team member. Hondo and Leroy disagree on how to handle a challenge to Darryl's fledgling business.