Detectives August Brooks and Chase McDonald meet when August and several officers are being overwhelmed by criminals in an explosive shootout. Chase arrives in his Porche and immediately neautralizes the situation with a grenade launcher. Moments later, August discovers that Chase is his new partner, and they are immediately assigned the case to track down a bomber - nicknamed the Daybomber - who has set off a series of explosions in his quest to warn people of the advances of technology.
Chase and August are at August's gym, where they are volunteering their time to help keep kids off the street and out of gangs. In the boxing ring is Andre, a young fighter determined to stay away from gang violence. But when word comes in that Andre's brother has been shot and killed by a rival gang, Andre swears to avenge his brother's death. Chase and August try to persuade him to let the police handle it, but Andre slips from their grasp in pursuit of the killer. The incident also brings back memories for Chase, who is struggling with unresolved guilt over his former partner's murder by a gang youth.
Chase and August are escorting an annoying accountant named Cecil Rusk - the star witness for the prosecution in mobster Marius Roma's tax evasion trial - to court when they are ambushed by Roma's brother and his thugs. After their car is destroyed, the trio escape on foot through a hail of gunfire. Alone on the streets of Los Angeles, they decide to head out of town, where they believe they'll be safe. But a mole inside the force is leaking information on the detectives' whereabouts to Roma's mob, and it's up to Captain Jensen and Det. Richardson to figure out who it is.
Ariel, a prostitute, is found dead. Nearby, a beautiful young hooker named Electra wanders the streets in a daze. Narrowly escaping Uzi-toting hitmen, she is taken into custody by Chase and August. Electra has amnesia and cannot remember what happened the night of Ariel's murder. Eager to crack the case, Chase and August are relieved of their investigation by Captain Jensen after orders from the mayor's office. Chase, convinced there is a cover-up in progress, refuses to drop the case.
When a group of criminals rob a computer chip assembly plant, Chase and August link the six million dollar heist to a local computer store. Posing as computer industry executives, the detectives visit the store and stage a robbery, pretending to save the day. Winning the confidence of the store's owner, Ray Bernard, they begin to work their way into his group.
Playing host to a COPS-like television show, Chase and August are out to catch the gangbangers responsible for a string of 211s around the city. The two-person TV crew tags along while the detectives tackle a 211 in progress and apprehend a couple of suspects. When Chase saves a store owner's 12-year-old boy just before a grenade erupts and the producer of the show says he plans to make Chase ""a star,"" August fears his partner's desire to be a movie star will slow their investigation.
Chase and August are eyewitnesses to a young man who throws a Molotov cocktail into a car right outside the gym. The perpetrator gets killed in the ensuing pursuit, but they find out that the car was registered to Carlos Altamarino, a known drug dealer. Chase is visited by an old college friend, now a CIA agent, who gives Chase a mysterious gold key for safekeeping and reveals that Carlos' operation has shifted power to a brother, a cousin, or perhaps even Carlos himself using an alias. The new boss carries the name Charlie Altamirano. Chase's friend is killed later, and the detectives work to figure out just what exactly is going on.
A young female tourist has been brutally murdered. The detecives suspect ""the Reaper,"" a deranged man who suddenly appears on the roof of the crime scene, screams biblical quotes at the officers, and opens fire. After a rooftop pursuit, Chase and August take him into custody. At police headquarters, Jensen explains that ""the Reaper"" is merely a mental institution escapee. The killer is still on the loose and plays with the detectives by leaving behind verses of a poem.
Arriving at the scene of a murder, Chase and August find that the victim is Bobby Roman, a favorite target of controversial shock-jock Jerry Maxwell. Roman has been shot in the head, just as Maxwell always advocated. When Chase and August confront Maxwell about the murder, the beligerent radio host denies involvement in the crime. But then a call comes into the station, and Maxwell is shocked to hear a devoted listener, Ward Valasco, claim that he killed Roman, and that he intends to kill all of Maxwell's enemies.
Arriving at a crime scene, Chase and August find a member of the Bulldog Crips gang shot to death. Chase is surprised to find a note containing rap lyrics pinned to his sleeve, which leads them to a rival gang member named Cage. After a daring chase, Cage is apprehended and interrogated by the detectives. Cage accuses A.K., a famous rap star, of the murder. Kicking in A.K.'s door, Chase and August square off with the musician and his manager, Frank Millan. But the detectives soon learn that nothing is what it seems, and the real killer is closer than they think. Meanwhile, Jodi's parents are in town.
When a wealthy foreign couple touring L.A. are found murdered and robbed, Chase and August are assigned to investigate. What they don't know is that these are not random killings, and that Russian mobster Ivan and his gang are plotting more crimes. The FBI demands that Chase and August focus only on the homicides and leave the robberies to them, but the detectives believe the two crimes may be connected.
A promising young boxer is beaten and left nearly dead. Arriving at the hospital, August and Chase intercept a hitman who attempts to finish the kid off with a lethal injection. They pursue the would-be killer through the hospital, finally stopping him with a jolt from a set of defribulator pads. Immediately, they sense that this case involves more than a random beating. August is visited by his former boxing coach, Frank, to whom he hasn't spoken since their falling out many years before. Frank says that he must tell August a secret that has been haunting him. But before he can reveal what he knows, Frank turns up dead, plunging the detectives further into mystery.
After a car chase with police, young Joey Morello, brother of a New York crime boss, barricades himself within a road-side burger stand, takes hostages, and demands a bus, plane, and money for an escape. Chase gains Joey's trust and talks some sense into the young man, getting him to drop his weapon. But when the cook panics and tries to escape, Joey is startled and draws an ankle-gun, and Chase is forced to shoot. The young kid dies, and his crime boss brother arrives in L.A. looking for revenge. Meanwhile, Chase is targeted by an Internal Affairs officer who is convinced he shot the young man for no reason because the kid's ankle-gun could not be found.
Chase and August thought they'd seen it all until they learn that the latest crimewave involves stealing kidneys from unsuspecting citizens. Racing to a downtown motel, they meet Andrew Green, the latest victim of the bizarre scheme. As Green is wheeled to an ambulance, he spots the prostitute who lured him to the scene of the crime where he was drugged and operated on, and Chase and August take off in pursuit. Det. Maria Vallejo goes undercover as a prostitute to assist in the detectives' investigation.
A van filled with illegal Mexican immigrants crashes in a violent explosion, killing many of its stowaways, and Chase and August arrive on the scene. Survivors limp with cuts and bruises, but the smuggler, the Coyote, has disappeared. One of the survivors tells the detectives that a man named Delgado had smuggled them across the border. Det. Maria Vallejo connects Delgado to a suspected sweatshop owner, and the detectives reluctantly put her undercover.
An abandoned church near August's home explodes into a fireball, triggered by an illegal methamphetamine lab. The next morning, he and Chase confront a group of bikers while trying to arrest one of them, and the bikers' trailer erupts into flames. It was being used as a meth lab. It's apparent somebody wants the labs out of business. Determined to crack the case, the detectives team up with Annie Mason, a new forensics assistant at police headquarters. Annie is able to turn up a suspect, a dangerous biker called the Falcon, with a rapsheet a mile long. But when he checks out the man's file, August is shocked to recognize the Falcon as Robert Hatcher, his former partner.
A car bomb explodes, killing the Vice President of Sawchuck Industries. In their search for suspects, Chase and August meet Meredith Nowell, a beautiful young volunteer at Green Planet, an environmental protection league. Meredith reveals that Sawchuck Industries had been dumping deadly toxins, which infected Los Angeles groundwater, killing a mother and daughter. When another Sawchuck executive is killed in an explosion, the detectives begin to suspect Joshua Duncan, the man whose wife and daughter died of cancer as a result of the poisoned water.
Teenagers Alan and Ian cruise down a city street smashing mailboxes, while Harold's younger brother, Ian, is forced to videotape their antics. The two older kids' thrill-seeking escalates when they smash the window of a store and accost the cashier. When the cashier opens fire, both he and Ian fall to the ground, and the other two take off running, Harold throwing the video camera into a dumpster before being caught by police. August and Chase question Harold at headquarters, but he has been threatened by Alan not to talk, or he and his mother will be killed.
Chase and August arrive at the scene of a murder on quiet Lily Lane, where Sheila Hanson has been stabbed to death in the bedroom. Her husband says he returned home to find his wife dead and a man robbing the house. The detectives chase after the perp and are shocked to find that it is David Jackson, a kid who belongs to August's gym and denies killing anyone.
Prisoners are being beaten to death at El Toro Prison. Guard Larry Clark plans to go to the authorities, but before he can talk, a bomb rips through his house, killing him and his wife. Chase and August suspect that Warden Brinkman is involved in setting up to-the-death fights between the inmates. Determined to crack the case, August goes undercover in the prison, but his cover could be blown when it's learned that Robert Hatcher, his former partner, is being transfered to the prison.
Art thief Richard Turpin, known as the Gentlemen Bandit, crawls through the skylight of a Los Angeles museum, only to be caught in the act by Chase and August, who apprehend him and haul him off to jail. The British government decides to extradite Turpin, accusing him of association with a radical faction of the IRA. Scotland Yard detective Wilhemina ""Willy"" Smythe arrives to collect Turpin, but her plans are soon thwarted when a terrorist named Riley shows up, who has plans of his own for the thief.
Chase and August arrive at the scene of a murder at a mental hospital, where a prominent psychiatrist has been stabbed to death. The suspect is a patient, Treat Donnelly, who is revealed to be Chase's cousin and vehemently denies killing the doctor. Several of Dr. Benning's colleagues fall under suspicion, and the plot thickens when it is learned that Elaine Hall, the dead doctor's beautiful assistant and one of the suspects, has more than one personality.
When former stars of the popular 1960's television show ""Captain Crimestopper"" are murdered, August suspects the show's star, out-of-work actor Wayne Berry, but Chase refuses to believe that one of his childhood heroes could be a murderer. At one of the crime scenes, the detectives apprehend a man disguised as the superhero, who turns out to be Berry himself, intent on finding the killer. When forensics concludes that Berry is not the killer, the actor is released, but an attempt on Berry's life at an autograph-signing puts the detectives on the trail of the one responsible.
Chase and August investigate a gun-running operation in which the prime suspect turns out to be recently-murdered CIA operative James Camden. Chase is seduced by Camden's former partner, but the romance is cut short when he discovers she may be involved with the plot as well.
Leonard Murdoch, a scientist for the high-tech firm Biotech, is murdered, and Chase and August suspect someone in his company wanted to keep him quiet. The detectives get a call from a Biotech whistleblower who tells them that the firm's CEO is planning to sell a top-secret biological chemical to international American enemies. Chase is convinced it's a cover-up for a government study of alien DNA, but before he and August can learn more, they are surrounded by military vehicles and men in black.
A prisoner named Murnau, who blames Chase for the death of his brother, is en route to prison when he escapes. Responding to the emergency call, Chase and August catch up with Murnau and pursue him. Their high-speed chase leads them onto a film set, which is being prepped for a car stunt. Both cars crash on the set, and Chase is knocked unconscious. In the hospital, friends and family visit the detective, hoping their voices will help revive him. Elsewhere in the hospital, Murnau plans his own visit to Chase.
A young woman is found murdered with fang marks on her neck, her body completely drained of blood. Chase and August attempt to question a suspect dressed as a vampire, but he takes off in a hearse, leading the detectives to a warehouse. They interrupt what appears to be a blood-drinking ceremony with a group of men and women, all dressed as vampires, and bring several ""vampires"" in for questioning. Wanda, the attractive leader of the group, falls for Chase and wants to protect him from the suspect they originally chased, who may not be what he thinks he is, but who may be just a dangerous.
Having just finished lunch in Chinatown, Chase and August are preparing to head back to the station when they see a drug deal going down. A chase ensues, and the detectives split up. When August finds Chase, he is lying in an alley, unconscious, with one of the men lying next to him dead. An eyewitness says she saw Chase kill the unarmed man, but Chase can't remember what happened before he was knocked out. August feels certain his partner is innocent and sets out to uncover the truth while Chase is suspended.
A group of Nazi skinheads demonstrate outside a black church, and a riot is narrowly prevented as Chase and August arrest a skinhead and a churchgoer. The next week, the church is burned to the ground, and a charred body is found inside - Duke Minks, a member of the Aryan Nation, who was arrested during the demonstration. The victim's uncle, Eddie Minks, also a member of the Aryan Nation, isn't happy that August is on the case, and warns that justice will be served, one way or the other. As the detectives dig deeper, they learn that the arsonist may be the person they least suspect.
Sam Como, owner of the Naked Venus strip club, has been murdered. His money and jewelry are in place, so robbery was clearly not the motive. Forensics reveals that Como was stabbed and beaten over time, so that he would die a slow, agonizing death. Chase and August question the dancers at the club and learn that a rival club owner, Johnny Roman, got into a fight with Como the night he was killed. The plot thickens when Roman denies the murder, telling the detectives that everyone hated Como, from his dancers to his wife, with whom Roman was having an affair.
Beth Landers, a young blind exotic dancer, hears a man being murdered as she walks home. The murderer sees Beth and is about to kill her, but a car accident draws attention to the scene. When the detectives arrive, Beth tells them that the killer has a limp and uses an inhaler. The killer, Larry Puzzo, doesn't know that Beth is blind and sets out to eliminate the only ""witness"" to his crime.
Chase and August investigate a string of gang-related robberies in Little Saigon, the Vietnamese area of downtown Los Angeles. One of the gang members turns out to be the son of August's Vietnam buddy, who died saving August's life. August is further shocked to discover that the boy's mother is the same woman he tried to help get out of Vietnam when he was coming back. They had gotten separated just seconds before their helicopter arrived, and August thought for sure she had died in the years that followed. She wants him to pull her son out of the dangers of gang life, but he knows too much for the gang to let him go.
Chase and August investigate the murders of two men: one an affluent, politically-connected businessman and the other a homeless man. They discover that the homeless victim was once a successful businessman who was going to testify against infamous criminal Bobby Cole. But the man was beaten so badly he forgot his identity and ended up on the streets. The detectives race to uncover Cole's secret before his hitman makes them the next victims.
The bodyguard of a famous actress, known for her seductive, deadly roles in low-budget B-movies, is murdered, and Chase and August are on the case. As the investigation progresses, the actress, considered a suspect, shows an interest in Chase, who has been ordered to protect her. But the real suspect could be closer than they think, and the least likely of them all.
Chase and August investigate the murder of a young fashion model who appears to be the latest victim in a string of recent model killings. Judith Sands, the L.A.P.D. psychologist, with connections from a previous (though short-lived) modeling career, convinces the detectives to let he go undercover to help find the killer. Chase and August are thrown onto the trail of a mysterious freelance photographer who has been hanging around the shows, and they are led on a wild chase before they can bring him in for questioning. But the suspect's DNA doesn't match that of the murderer's, and Chase and August must let him go and continue the search for the killer, who has decided on making Judith his next victim.
Michael Mills, a convicted killer, escapes from prison and seeks revenge on the three cops who put him there. He kills two of them and goes on the hunt for the third, August Brooks, who has gone camping with Kendra for two weeks. Chase is still in Los Angeles, investigating the murders of the two officers. After putting the pieces together, he realizes that August is in danger and tries to find him at the remote campsite where he is vacationing before Mills does.
Lane Healy, a competitive weightlifter, is the prime suspect in the gruesome beating-death of his wife, but he maintains his innocence. Chase and August investigate and meet another weightlifter, Terry King, a famous world champion. King has promised a victory at this year's ""Mr. Galaxy"" competition. When several of the top competitors, including Healy, are somehow removed from the contest, King becomes a suspect.
August goes undercover as Jake Rheams, a notorious East Coast drug lord, who arrives in Los Angeles to make a deal with the Carletti crime family. August meets with Gina Carletti, the beautiful and seductive daughter. Alex Zota, the boss' right-hand man, suspects August from the start, never really believing that he is the real Jake Rheams. Meanwhile, Chase must back up his partner the best he can, including an interrogation with the real Rheams, who is being held at the station. August is tested by Zota, and only Rheams has the information that can help Chase save his partner's life.
While August recuperates from his injuries from the previous episode, Chase and D.E.A. agent Jack Lawson work together to rescue a mysterious accountant who has been working for Bobby Cole. The accountant, known simply as the Monk, is brought into police custody after a daring rescue by Chase and Lawson. But fearing for his life, the Monk refuses to talk. An F.B.I. agent, Shoenrock, has come to take the Monk into custody, but Chase believes that he'll be able to get the Monk to talk, but his and Lawson's plans are wrecked when the two discover that Shoenrock may not be who he claims to be.
A judge, a housewife, and an attorney are all killed by toy-like devices. While searching for the victims' possible connection, Chase and August discover that all three were involved in a court case years earlier in which a woman, working in a college laboratory, was killed in an explosion set off by a radical activist. At the conclusion of the trial, the killer was set free. Afterwards, the woman's husband, Karl Shipman, set out for his own revenge. After killing the man who killed his wife, Shipman was arrested and sent to prison for life. But Shipman wasn't finished with avenging his wife's death yet, and gave the orders for murders from prison.
Chase and August must catch Patricia and Johnny, a mother and son bank robbing team that is responsible for a string of heists and murders. One of the duo's victims at the most recent heist was Gary, Annie's boyfriend. Annie witnessed the murder, and there is an attempt made on her life. Chase and August investigate the armored car company to see if there is a chance that the last heist was an inside job. They question the scheduling man, Morty Feinberg, who appears to be completely in the dark regarding the robbery. We soon learn, however, that he is linked to Patricia and Johnny, and has been helping them set up their heists. Annie works overtime to help Chase and August with the case, while Patricia and Johnny insist on pulling one more job with Feinberg, but it just might be their last.
Chase and August must assist the Army in catching Major Lauren Wiley, a C.I.D. officer accused of selling arms to the underground. Lauren is an old girlfriend of Chase's from college, but Chase insists that he works the case. Captain Randy Geddis leads the Army investigation and demands that Lauren be brought back to him immediately. At one point, Chase and August think they have Lauren cornered, but before she escapes, she tells a different story. She claims that Geddis is the crooked one, selling weapons on the black market to Bobby Cole. Chase and August don't know who to believe.
Danny Bledsoe, a key witness set to testify against crime boss Alfredo Matessa, is escorted to Los Angeles by Nicole Stockman, a beautiful tough-as-nails detective from San Francisco, where he had fled to. From the start, Nicole makes it very clear to Chase and August that she resents doing all the work to catch Danny in San Francisco, only to have them receive all the credit during the L.A. trial. And Danny isn't known as ""The Eel"" for nothing. As Chase and Nicole are transferring Danny to a safehouse, he escapes. Afraid that the police can't protect him from Matessa, Danny decides to take his chances on the streets. With time running out, Chase, August and Nicole have to catch the Eel before Matessa's thugs do.
A motorcycle cop is shot and killed during a routine traffic stop. The killer's car is traced back to James Burquette, an attorney who had reported the car stolen earlier that day and is shocked to find that it was used in a cop slaying. When another officer is killed, August goes undercover as a motorcycle cop, hoping to lure the killer into striking again.
Professor Larry Benton, a former teacher of Augusts', is brutally killed outside a jewelry store by thief Willie Mathers. August is devastated upon his arrival at the crime scene, having just had lunch with Benton moments ealier. August vows to catch Mathers, but is shocked when Benton's twin brother shows up from.
A Western memorabilia collector is found murdered, and among the victim's belongings is a laptop containing August's name. August figures out that his name was listed among the descendants of Buffalo Soldiers, a special troop of black soldiers that fought during the Civil War. This brings up a part of August's past that he is ashamed to discuss: his great-great-great-grandfather, Augustus Brooks, was given a dishonorable discharge from the Army when he allegedly deserted his troop with three other soldiers, claiming to have been given a map leading to a gold mine that was never proven to exist. August's Aunt Maisie is attacked in her home by a thug, hired to steal a portion of the old map. The pieces have been handed down to each generation, and now someone is attempting to put the pieces together and lay claim to the gold.
After three leading West Coast drug dealers die under suspicious circumstances, Chase and August suspect their old nemesis, Bobby Cole, is trying to claim all the drug action for himself. As Los Angeles prepares to host an international drug summit, the detectives investigate Cole through the usual legal channels while he ruthlessly carves out the competition and prepares to strike a deal with a Colombian drug lord.
After witnessing Nicole Stockman's murder on the order of Bobby Cole, Chase becomes a loose cannon. August pleads with his partner to follow legal avenues to catch Cole, and Captain Jensen suspends Chase after he destroys important financial papers belonging to Cole. Shoenrock claims that Stockman was suspected of working with Cole. Chase is furious, knowing this could never be true. Cole meets with Shoenrock, who is revealed to be undercover, acting as an accomplice, and tells him of his plans to execute the Colombian drug minister at the drug summit. Meanwhile, Chase goes renegade and visits a weapons dealer, purchasing some heavy duty weapons for his own personal use against Cole. After a huge battle in the streets of Los Angeles involving semi-trucks, helicopters, and rocket launchers, Chase ends up on a pier with Cole, weapons drawn in a stand-off, each prepared to take the other down . . . for good.