The SWAT team works together with former member, Jim Street to find a woman and her son who are running from an international drug cartel. Hondo makes a distressing discovery about his incarcerated friend’s teen son. Luca mulls over a government program that allows officers to buy homes in the at-risk neighborhoods they police.

Hondo and Lina go undercover to infiltrate and take back a cruise ship that’s under siege by drug smugglers who will execute passengers if they detect police on board. Street enters the SWAT Training Academy and finds the competition fiercer than he expected.

The SWAT team tries to determine the next diamond dealer to be robbed by a group of highly organized thieves executing heists across downtown Los Angeles. When Hondo is emotionally affected by a suspect’s death during the case, he seeks comfort from his mother. Street worries that his SWAT training academy instructor has a personal vendetta against him. Chris contemplates an unorthodox relationship offer from the new woman she’s dating.

The SWAT team races to find a stalker pursuing a social media star, after the online celebrity's dangerous admirer turns a fan event into a shootout that endangers Jessica.

The SWAT team sets out to recover dozens of DNA evidence kits stolen from an LAPD crime lab and bring in the crew responsible, after a close friend of Hicks is harmed during the theft. Financial strain at home makes it difficult for Deacon to focus on his role as leader of the SWAT division’s annual holiday toy drive.

Jessica and Chris go undercover in Mexico, alone and without back-up, to save a Mexican federal agent kidnapped by a drug-dealing gang that Jessica helped bring to justice years before. Also, Hondo’s mother, Charice, worries he’s under emotional strain when he engages in a series of small home renovation projects in her home.

Hondo reunites with an old flame, FBI Special Agent Elle Trask, when the SWAT team works with the FBI to bring in a separatist group with weapons-grade plutonium. Also, the SWAT team worries they will lose an annual law enforcement charity competition to the Los Angeles Fire Department.

The SWAT team struggles to maintain peace on the eve of a Los Angeles LGBTQ pride festival after a hate crime sparks citywide anger that ignites further violence. As Chris grows anxious for her fellow LGBTQ community members calling for retribution, the festival reunites Commander Hicks with JP, his estranged gay son. Also, Street worries his mother will be sent back to prison after she fails to check in with her probation officer, and Deacon gets unexpected medical news regarding his newborn daughter.

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 discovers a new version of PCP with ties to an escaped drug dealer who created a version that ravaged the city decades earlier. Tan’s personal ties to the case emerge when he brings in his mentor, Ben Mosley, the former lead detective on the original drug case, to help. Also, Chris weighs a major decision regarding her romantic relationship with Kira and Ty, and Hondo’s patience is tested by his new familial responsibilities.

The SWAT team races to locate the next place a lone gunman will strike while he is at large in Los Angeles. Also, Hondo takes some time away from the team to pursue an investigation that hits close to home, and Jessica is presented with an unexpected opportunity.