When the SWAT team is called in to work on their day off to end a hostage situation, they discover one of the captives is a wanted felon. When Hondo saves his sister after she's been roofied at a nightclub, he uses his day off to hunt a serial rapist.

The SWAT team pursues a group of unknown assailants responsible for a patrol officer’s death before tension in the city between the police and the community explodes. Also, as Chris reels from the revelation that she knew the patrol officer who was killed, Deacon and his wife, Annie, prepare to welcome their newest child.

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.