A locally born SWAT sergeant, former Marine Daniel "Hondo" Harrelson (Shemar Moore), is newly tasked to run a specialized tactical unit that is the last stop in law enforcement in Los Angeles.
Hondo (Shemar Moore) leads his S.W.A.T. team in a race to find four escaped convicts ahead of the crew led by Mumford (Peter Onorati). Hondo's leadership is called into question when Street (Alex Russell) disregards protocol.
When Hondo's imprisoned childhood friend asks him to protect his son from gang violence, the favor brings SWAT into contact with a new local crime outfit. Also, when Luca's grandfather, a SWAT legend, passes away, he struggles with his grief and a painful family secret.
Hondo and the SWAT team are forced to work over their Christmas vacation when a drug cartel is out for blood after their cache of gold bars is stolen. Also, Jessica draws the attention of Michael Plank, president of the Police Commission, when she approaches him with her ideas on how to improve the SWAT division.
When a misconduct complaint filed against Hondo gets him taken off active duty, Deacon steps up to lead the team in finding a robbery crew that is hitting marijuana dispensaries. Also, when Tan notices a similarity between the current robberies and a case from his time with Hollywood LAPD, he asks for help from an informant with whom he has a complicated history.
As the SWAT team goes inside a prison riot to rescue civilian hostages, Hondo suspects the inmates have an ulterior motive behind the uprising. Also, when Deacon's wife, Annie, stops by headquarters to celebrate Deacon's 10th anniversary with the SWAT division, her visit takes an unexpected turn.
Hondo teams up with an old DEA friend, Special Agent Katrina "K.C." Walsh, on a task force aimed at unmasking the secret leader of a fentanyl drug-smuggling ring. Also, Jessica and Michael Plank, president of the Police Commission, begin implementing her new law enforcement community initiatives.
Hondo and the SWAT team join forces with the FBI on a manhunt to find members of a militia group planning a domestic terror attack by weaponizing cyanide. Also, as Jessica's new police initiatives with Michael Plank, president of the police commission, move forward, she braces herself for the negative impact the plans could have on her relationships within the department.
As the search for a violent gang leader lands Street (Alex Russell) in the middle of a heated immigration policy debate, Commissioner Plank (Peter Facinelli) discovers the truth about the relationship between Hondo (Shemar Moore) and Jessica (Stephanie Sigman).
Hondo (Shemar Moore) must track down a serial killer who escaped justice by faking his own death. Hondo worries about the mental health of his teammate Buck (Louis Ferreira) in the aftermath of his firing.
The job becomes personal for Hondo when his criminal informant friend is killed while seeking information about a robbery crew that a joint SWAT and FBI task force is trying to capture. Also, when the FBI task force leader acts erratically, Jessica worries the woman's behavior will endanger the team in the field.
When a young heiress is kidnapped for ransom, Hondo and the SWAT team go on a citywide search to bring her home before she is harmed. Also, the team worries that Mumford is moving too fast when he announces he's getting married for the fourth time.
As Hondo and SWAT work to de-escalate a hostage situation in which an ex-convict is holding a local family captive, the mission takes a dangerous turn that impacts the team. Also, when Street tires of his complicated romantic entanglements, he agrees to let Chris make over his online dating profile.
Hondo confronts his long-held resentment towards his ailing father, Daniel Harrelson Sr., when he and his sister, Briana, try to convince their dad he's no longer well enough to live alone. Also, when the SWAT team works as patrol officers for a day, Chris is partnered with Mumford, who intends to make her a surprising offer.
Jim Street debates whether or not his mother, Karen, should live with him upon her prison release after Hondo and Chris warn him against it. Also, Hondo and the team are assigned to protect Irina Zemanova, a high-profile Russian journalist visiting Los Angeles, from being assassinated.
Hondo's life and career are endangered when his bosses and his godson's kidnapper, Jae Kim (Kelvin Han Lee), discover he's been secretly surveilling Kim with the help of retired DEA agent Katrina Walsh (MC Lyte). Also, Street and his newly paroled mother, Karen (Sherilyn Fenn), both have trouble acclimating to her prison release.
Hondo and Deacon must apply all their SWAT training and skills to evade a gang of armed mercenaries hunting them in the Angeles Mountains following an ambush. Also, Chris oversteps in an attempt to help a female SWAT trainee she suspects isn't being evaluated fairly.
A fake 911 call puts Hondo and the SWAT team on the hunt to stop a terrorist group from executing bombing attacks on local communities. Also, Street's relationship with his recently paroled mother, Karen (Sherilyn Fenn), jeopardizes his career, and Jessica is thrown a curveball by her colleague, Michael Plank (Peter Facinelli), president of the police commission.