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.

Tan is left reeling when his girlfriend is kidnapped, and 20-Squad must race to track down a violent cartel leader who may be behind the abduction.

After an explosive accident at a fruit-packing facility staffed by prison workers, six inmates escape and scatter across the city. Tasked with chasing down the fugitives, Hondo and 20-Squad discover that the worksite explosion was no accident, and that the escapees are working together to carry out a high-stakes robbery. Also, Commander Hicks packs up his office, preparing to vacate the SWAT commander's post, and Gamble gets sobering news about her jailed father.