The SWAT team faces difficult reminders of a past school shooting when they receive a warning that a copycat plans to re-enact the crime. As the team races to stop the new threat, they flash back to the day of the tense first mission.

The abduction of Luca and Street’s neighbor sends the SWAT team in pursuit of a home invasion crew targeting domestic workers to gain entry into upscale homes. Also, the SWAT division prepares to help Mumford mark a major career milestone.

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 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.

The SWAT team finds itself under internal investigation after a civilian is killed as they attempted to bring in the city’s most wanted criminal. As the mission details are revealed, the force’s internal affairs team calls Hondo’s leadership into question.

The SWAT team goes in pursuit again of the militant group The Emancipators, when the criminals hold a live stream kangaroo court to publicly execute city politicians. Also, Hondo fights to lift Darryl’s spirits; Deacon feels unworthy as he prepares to receive one of the LAPD’s highest honors; and Street catches a break in the search for his missing parolee mother.

The SWAT team hunts for a band of criminals re-enacting the crimes of the infamous Symbionese Liberation Army. Seeking expertise on the original crime spree in the 1970s, Luca and his father review the files of Luca’s late grandfather who worked for SWAT during the era of the original crimes. Hondo experiences discrimination from a fellow officer during a SWAT training seminar for local law enforcement in Arizona.

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.

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 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.

The SWAT team tries to zero in on the next target of a carjacking ring that’s using deadly force to boost luxury vehicles all over Los Angeles. Also, Hondo takes a big step to help his childhood friend’s incarcerated son, Darryl, and SWAT team leader Mumford weighs a major decision.

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 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.

The SWAT team races to find a militant group that escaped their capture months earlier, when the criminals take hostages in exchange for a $500 million ransom from five corporations they deem corrupt. Also, Hondo’s emotional turmoil begins to affect his team leadership.

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 engages in a standoff with human traffickers holding child hostages when a major earthquake hits Los Angeles during their operation and compromises the takedown. Hondo forms an unexpected personal connection with Deputy District Attorney Nia Wells. Jim Street has trouble adjusting to his new life as a patrol officer.

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 suspects an ulterior motive when Nina's estranged husband, US Marshal Eric Wells, requests the S.W.A.T. team’s help with apprehending a fugitive who is robbing drug cargo shipments. Jessica is forced to implement departmental budget cuts. Street makes a heartbreaking discovery about his mother.

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.

The SWAT team is enlisted by Hondo’s new romantic interest to protect the jurors of a high-profile bribery trial, after some of them are targeted by organized crime in a series of fire-bombings.

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 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.