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.

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.

Hondo is conflicted when Leroy, his incarcerated childhood friend and Darryl's father, asks him to speak on his behalf at a parole hearing. Also, SWAT helps the FBI track down a mob informant on the run from the crime family he is meant to testify against, and the team dynamic becomes complicated when Street and Tan sign up for a leadership competition Chris has been training months for.

Hondo is conflicted when the mayor asks him to be the public face of a new outreach campaign meant to improve the LAPD's stature within the Black community. Also, the team's search for a lone bomber reminds Tan of a difficult chapter in his childhood, and Chris pushes herself even further to surpass Street and Tan in a SWAT leadership competition.

The SWAT team goes on the hunt for a sniper who is targeting the Los Angeles Fire Department by setting fires around the city to lure in unsuspecting engine companies. Also, the rivalry between Chris, Street and Tan ratchets up when Tan finds out there’s an internal betting pool on which of them will win the SWAT leadership competition. And, Street and Molly’s relationship is strained by his complicated history with his imprisoned mother.

SWAT searches for a group of extremists carrying out coordinated attacks against local businesses. Also, Deacon and his wife, Annie, find themselves at odds when Annie wants to enroll their daughter, Lila, in private school.

A tragic mission leads each member of the SWAT team to contend with their emotional distress in varied ways.