Jack and Paco get a lead on the serial killer’s next possible victim and race against the clock to try and track her down before the killer gets to her; Kent struggles over whether or not to invite Betty to take part in his murderous rampage when it becomes clear that she doesn’t trust him and may leave him, and Jack and Paco continue to search for Karen, who has disappeared from the club.
Betty struggles with the revelation that Kent is a serial killer when he gives her a copy of the novel “Phantom of the Opera” and asks her if she can love him the way Christine loved the Phantom. Meanwhile, Jack and Paco trace the ownership of the lair and identify the body they found in the floorboards as Vera Bennett, a former librarian. During the investigation at the library where Vera used to work, they run into Karen and Diver, who confess about a letter Kent sent them. Hoping to get additional clues, they are shocked when they uncover a huge surprise on a bookshelf. Later, Dianne points out Jack, and the killer might not be so different after all.
Jack focuses on a woman from the past who may have been the catalyst for the murderer’s current killing spree; Betty decides to go all-in as Kent’s partner, and together they troll a club in search of a victim; Karen is offered a job with Rolling Stone, which does not please Diver; a menacing old flame of Betty’s reemerges and sets his sights on trying to reignite their troubled past; and Dianne finds herself in dire straits when her allegiances are questioned by a powerful drug lord.
Jack and Paco ask LA Notorious to run another story about the killer, with the shot of Kent as a child on the front cover. This leads to one of Kent's schoolmates contacting the police, who names him as Cooper Flynn. After the story is published, Kent visits Karen at her home, waking her in the night. He asks her to be his voice, not the police's. In return, Karen asks for a personal interview with Kent. Elsewhere, Diver is trying to locate Bucket, unaware he is dead and that Dianne has taken his place as manager of the drug ring. He later spots Jack and Dianne kissing, and takes photos of the two. The detectives decipher that the killer must work in the motor industry, due to his access to vintage cars. They also theorize that these cars are where the murders take place. This discovery leads the police to Kent's auto shop, where Jack finds blood in the water pipes. Kent later arrives at the shop, but drives away before any police officers can see his face. Meanwhile, Betty's old flame, Jimmy Lovett, suspects Kent of being a drug dealer. He trades his silence on the matter for sexual favors from Betty, who reluctantly agrees. During their meeting one night, Betty stabs Jimmy to death with a knife gifted to her by Kent. Later, Kent babysits his neighbor's daughter, Mary, who becomes suspicious of Kent after watching a TV report on the killer.
Jack and Paco question Kent's co-workers and find out his "real" name, Kent Grainger, but no records are found about him. When going through files from the auto shop, Paco discovers a Xerox of Kent's I.D. Kent visits Betty at the hospital; she takes him to the morgue so they won't be seen, where he proceeds to break up with her, fearing that the police will catch them both if they don't part ways. Kent dyes his hair in an attempt to conceal his identity. His acquaintance, Bobby, creates new I.D.'s for him; he then ties her up and locks her in a closet. Meanwhile, Betty disguises herself as a makeup lady and visits Jack's wife, Allison, at their home. When leaving, she takes a photo of the family and a set of keys to the house. Mary calls the police's hotline to give Kent's address, but her dyslexia mixes up the house number. Elsewhere, during a live interview on Eyewitness News, Karen gets a call from Kent, who says that the story hasn't yet had its climactic ending. Diver identifies a song playing in the background of the call as "Suicide Solution" by Ozzy Osbourne, and suggests Kent might kill himself. When the police realize Mary's mistake, they arrive at her house just as Kent causes an explosion in his home across the street. Betty arrives home, thinking Kent is dead, but he surprises her with the fact that the burned corpse belongs to Jimmy. As the two kiss, the residents of Los Angeles think the Hollywood Slayer's reign of terror has ended.
Diver and Karen contemplate running a story about Jack's affair with Dianne, whom they think is a drug dealer, unaware that she is actually an undercover cop. Jack is doubtful that the case is over, thinking the corpse isn't Kent's. When Kent goes to snoop at LA Notorious, he finds the photos of Jack and Dianne kissing. Thinking the Hollywood Slayer search is over, Paco requests to lead his own case. Later, he and Jack are told that the charred body doesn't belong to Kent; Jack then finds the photos of him and Dianne on his car windshield. Karen confronts Dianne about the affair, unaware that the killer is still at large. Meanwhile, Kent and Betty plan an alibi for her for the night Jimmy disappeared; Kent plants Fly Brand cocaine in Jimmy's car, while Betty plants an auto shop bill in his house. Dressed in costume, Kent approaches Dianne at her club and buys Fly Brand off of her. Betty makes a tearful statement to the cops about having an affair with Jimmy in order to protect herself. Elsewhere, Kent breaks into Jack's house and leaves a copy of the photos on his daughter's bed. Jack, angry about the killer having power over him, starts a fight with Paco, but eventually tells him what's going on. When Jack arrives home, he comes clean to Allison, who storms out of the house. Paco informs Karen and Diver that the killer took photos from their office and now Dianne is in danger; he then goes to Dianne's apartment to warn her, and the two leave without noticing Kent hiding. Jack returns to the Whisky on the advice of Dianne, and is approached by Kent in a disguise.
Kent approaches Jack, saying he is not the killer. As a concert begins, Kent runs off, with Jack chasing after him. Jack catches him and takes him into custody. Karen tells Diver that Kent called her again, and his request for her to write a piece on Jack and Dianne's affair convinced her to do the opposite. Allison finds out that Vicki lost her virginity, as well as that Vicki knew about her father's affair. Kent is granted a phone call; he calls Betty, setting their plan of getting him free. During the interrogation, Jack makes Kent look at all the compiled evidence. Kent continues to claim that he is being framed. He says that his grandfather is the killer, but Jack isn't convinced. Kent then claims that it was Dave Keller, his co-worker, but no evidence can back the theory up. Karen does a TV segment warning the people of Los Angeles to stay safe. At the club, Dianne is told that Karen has been looking for her, as well as a "blonde chick" which later turns out to be Betty. Paco tells Jack that they found Fly Brand cocaine and a missing girl's ring in Dave's car; Jack says that Kent most likely planted them there. On TV, Karen tells the world that she is the voice of Kent's victims. Betty kills another girl and drops the body at the Santa Monica Pier, prompting Jack to realize that Kent has a partner. His captain gives him an hour to find Karen, in order to identify the Hollywood Slayer, or Kent goes free. The body at the pier ends up being Karen's. Back at the precinct, Jack angrily lashes out at Kent as he leaves custody. Six months later, Dianne returns to work at the police station. Paco and Jack vow that the next time Kent and Betty make a kill, they will catch them. Kent and a visibly pregnant Betty are shown living in Chicago. The series ends with Kent dedicating Foreigner's "Feels Like the First Time" to a new victim.
