Street's partner, officer Rob Duran, is killed in the premeditated police assassination by two brothers bent on revenging their father's death. That and subsequent police killings serve to shape the psychology of Lt. Dan "Hondo" Harrelson's newly formed Special Weapons and Tactics team, "S.W.A.T." The team's task is to combat high risk, contemporary, urban crime as a strike force. The team consists of James Street, David "Deacon" Kay, T.J.. McCabe, Dominic Luca, and Harrelson. "S.W.A.T."'s first assignment is an acid test of their ability to survive as individuals and as a team. Their rigorous training is literally a fight against time.
Three members of Joey Hopper's "family," including newcomer Judy Collins, engineer Hopper's escape from a prison's hospital ward. After executing an assistant District Attorney, Hopper sends a recorded message to "Hondo" that he will be the next victim and that he also intends to punish the jury that found him guilty of other homicides. Russ Collins, owner of an underground newspaper which has published sympathetic articles about Hopper, refuses to admit knowledge of Hopper's whereabouts until "Hondo" informs Collins that his daughter has become a member of the treacherous cult.
In a period of a year, model Janet Warren dated three young men, and each has been killed by a sniper's bullet. Police have been unable to find motives or suspects. Since Janet is the only link, Hondo assigns officer Jim Street to pose as the beautiful girl's latest boyfriend in a plan to draw out the sniper who apparently has Janet under constant surveillance.
Hondo and his men have been working around the clock on cases such as a food market heist and a kidnapping investigation, when lady journalist Meredith Cooper reports, with police department approval, to spend several days with the S.W.A.T. team. Ms. Cooper's presence creates problems. Her beauty is distracting. Her manner is pushy and her opinion of policemen is anchored somewhere below sea level.
Vincent Ritchie, serving a prison sentence, agrees to expose the secrets of a crime syndicate before a Senate committee when he learns of "family" plans to insure his permanent silence. As he is transported with a police escort from the penitentiary, Ritchie is gravely wounded in an ambush attack which claims the life of a police officer. While doctors fight to save the convict's life, Hondo's team and other S.W.A.T. units station themselves throughout the hospital, awaiting an expected attempt to finish Ritchie off.
Bo Pritchard is a veteran police officer who also served with Hondo in Vietnam. Having completed S.W.A.T. training, Pritchard all but begs Hondo to give him a chance to work on the team until "Deacon" Kay recovers. But going into action with Hondo recalls memories of jungle warfare to Pritchard whose hostility and resentments eventually pull him into an emotional breakdown.
After completing S.W.A.T. exercises at a movie studio, Street realizes that he left his beeper on the lot. When he and his girlfriend return to collect it, they are trapped in the deserted studio by an embittered stuntman, who is planting explosives with the intent of blowing up the lot as an act of revenge.
As Hondo Harrelson and the S.W.A.T. team investigate the theft of an armored car, T.J. McCabe is spending his lunch hour with his fiancée, Susan, who is public relations representative for the Miss American Beauty Pageant. As Miss New Mexico tries on the crown and scepter, the armored car thieves attempt to steal the jewels, taking Susan and Miss New Mexico as hostages.
While leading the team in the rescue of several women being held hostage by two known killers in a massage parlor, Hondo is grazed by a bullet across his temple. He refuses to take time off for tests until dizziness and blurred vision force him temporarily to relinquish his command to Lt. Purcell, an officer whose methods and personality have a demoralizing effect on the S.W.A.T. team.
After making a careful study of S.W.A.T. methods, Frank Hunter, a recently dismissed parole officer, recruits a group of ex-convicts with special skills. Then, after setting off a series of false S.W.A.T. calls throughout the city, Hunter and his well-armed specialists help themselves to a fortune in rare gold coins from a heavily guarded rare coin auction.
Following a training exercise with S.W.A.T. officers from another division, Hondo and Street find the dead body of officer Frank Crane with the words "Kill S.W.A.T." pinned to his chest. The murder of Crane is the forerunner of a series of attempts to wipe out S.W.A.T. by brothers Mike and Simon Bishop and their fanatic sister-in-law, Joanna, who is convinced that the death of her husband was the result of S.W.A.T. "brutality."
Mel Lang and Ralph Costa have served sentences in prison after being framed by one Carl Rigby and arrested by Hondo Harrelson. When S.W.A.T. is called upon to assist police in evicting heavily armed brothers Will and Johnny Brewer from a home taken over by Rigby, Lang and Costa plan to execute Hondo and Rigby and create evidence pointing to the Brewer Brothers.
Runaway teenager Kathy Benson, seeking shelter in the warehouse, calls police when several men break in. Before fleeing the scene, Kathy gets a clear look at the leader, Gregg Colby, a prominent citizen and former U.S. Senator, attempting to solve his money problems by stealing from his own warehouse, collecting the insurance, and later selling his own "stolen" merchandise. He pretends to offer assistance to police investigating the case so that he can silence the only eyewitness, Kathy.
Radio repairman Paul Julian has patched in on the S.W.A.T. radio band so he can show up at a scene of police action, where he can observe and judge each case from a concealed position. when Julian decides to punish two disarmed gunmen who have been talked into surrendering by Lt. Hondo Harrelson, S.W.A.T. is suspected of causing the senseless killings.
Howard Wilson is jailed and his partners, Mike Simon and Frank Peterson, escape before S.W.A.T. moves in to combat a race track heist involving a female hostage. Wilson is on the brink of revealing the names of his partners when a high-powered attorney, Jason Bridges, assures him that Simon and Peterson are planning to free him at all costs--even if the price involves the lives of court personnel when Wilson goes to trial.
D.A. Ainsely Stevens holds secret information which could convict two syndicate chieftains of capital crimes. Because Stevens insists on saying nothing until the grand jury convenes, and because police believe the mob has put out a "major contract" on Stevens, S.W.A.T. is assigned to guard him. But enforcer Mario Rosetti plans to abduct the prosecutor's daughter, Tory, and keep the girl until the father cracks. Oblivious to the danger, Tory is out for kicks as police and crooks try to track her down.
Marco, an arsonist-killer posing as a fireman, engineers a fire during Southern California's dry season in the area's most affluent neighborhood. While looting the evacuated home of a wealthy couple, one of Marco's men kills a fireman. When S.W.A.T. is called in to locate a possible sniper, T.J. McCabe is shot and Marco escapes with a truckload of loot.
Millionairess Doris Bristol has brought gems into the hospital where she is undergoing cosmetic surgery. Her bodyguard, John DeLeon, is slain after he spots criminal Frank Malloy posing as a dying patient (part of a plan where a woman doctor and he plot to steal the jewels from the socialite). Hondo and his men, who are at the hospital putting together a Christmas party in the children's ward, find themselves on duty when the discovery of DeLeon's body leaves Mrs. Bristol unprotected and in apparent jeopardy.
Hondo Harrelson and his team are called upon to investigate robbery-homicides in which powerful drills and cutting equipment have been stolen. Meanwhile, Dom Luca is dating a student, Sharon Merlingdale, who is being carefully watched by Mark Worth, one of the killer thieves. The more Sharon sees Dom Luca, the more convinced North becomes that the girl must be eliminated.
Bud Haskins, disowned after marrying a girl whom his father, John Haskins, disapproved, decides to help three "professionals" crack open the safe in the elder Haskins' warehouse. Bud is unaware that the thieves are actually after a huge arsenal of sophisticated, unmarked weapons that have been secretly imported for sale. Bud is slain after helping the criminals burglarize the warehouse. Although S.W.A.T. is assigned to investigate the burglary-murder, John Haskins recruits members of a tough Eastern mob to find the killers of his son.
Lt. Eddie Chew is assigned to aid Lt. Hondo Harrelson when an elderly shop owner is fatally beaten by an illegal Chinese alien working as a shakedown man for Albert Parker, the Caucasian leader of what appears to be an all-Oriental crime syndicate, a deadly drug and protection ring. Hondo begins to doubt Chew's integrity when it becomes obvious that Chinatown criminals are being given secrets of his investigation.