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.

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.

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 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.

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.

The SWAT team searches for a rogue member of an extremist group planning to attack the memorial service of a famous musician who was outspoken about police brutality. Also, tension mounts between Hondo and Leroy, Darryl's father, when Leroy is released from prison early.

Chris brings the SWAT team into her personal mission to save a teenage girl from a charismatic, predatory religious leader using his church for illicit gain. Also, Hondo receives troubling news about Darryl related to Leroy, Darryl's father, being released from prison, and Tan's wedding planning hits a snag.

Mumford returns to work a 15-year-old cold case that holds a personal connection and leads to the discovery of a dangerous drug ring. Hondo is leery of Leroy’s motives when he discovers the recent parolee is seeking funding for a new business venture with his son, Darryl.

As the team works to stop a violent attack on the city, they're forced to confront the group responsible for the death of a team member. Hondo and Leroy disagree on how to handle a challenge to Darryl's fledgling business.

The team races to rescue victims of a sex trafficking ring that is preying on disenfranchised women. Also, Hondo finds himself at odds with Leroy and Darryl over the future of their business, and Street confronts Chris about meeting with his hospitalized mom.

The bombing of a Los Angeles police station puts the city on edge, leading the team to a final showdown with a group of domestic extremists. Also, Hondo faces the fallout from a bold decision that threatens his future, and Tan takes a big step in his personal life.

The SWAT team partners with the DEA to locate stolen rocket launchers smuggled into Los Angeles, high-power weapons with new technology capable of cutting through armored tanks. Also, a personal issue for Tan arises when a colleague is hurt in the field; Hondo's inquiry into the arrest of a homeless veteran for Leroy, Darryl's father, sparks an idea for a new policing initiative; and Luca suspects the mother of his mentee, Kelly, wants to date him.

When a home invasion turns deadly, the team embarks on a race to track down priceless antique artifacts before any more lives are lost; Leroy enlists Hondo's help after an overdose hits close to home.

As 20-Squad scrambles to track down a cold-blooded sniper terrorizing Los Angeles, Hondo discovers a link to his own South L.A. neighborhood that brings a personal twist to the hunt for the deadly shooter. Meanwhile, Tan finds himself questioning his leadership abilities while Powell and Alfaro compete in a classic game of SWAT tag.