The Ridley cold open features Ridley fast asleep on the couch, dreaming the house is on fire. It was only a dream; the man responsible for the fire, Michael Flannery, is locked up, unable to see his mother in her final hours. It's too late now; she's dead; Ridley monitors his funeral attendance, watching Michael greet younger brother Cal (Nico Mirallegro) at the graveside service. Michael complains he's not allowed to attend the wake, but with his associates from the Donnelly gang there, Ridley's not about to be lenient. Besides, he has his family's grave to visit. He's not the first one to stop by either, fresh flowers from the gang, signed "Adam Donnelly," are already resting there.
Ridley: Michael Flannery has nothing to do with this.
Meanwhile, this week's case involves the death of Dr. Patrick Elliot (JP Conway), a depressed LGBTQ+ psychologist working with ex-offenders, meeting a bitter end off his balcony. Dr. Newsome determines an unseen assailant threw him; his neighbor, Diane Blaine (Kellie Shirley), suggests sex workers visit regularly. However, the local kids and the paint on his door suggest that's homophobic bigotry talking. Carol has to dash, so Ridley and Darren see Patrick's boss Dr. Samanatha Larsson (Suzanne Packer). She says Patrick was on enforced leave for his mental health issues; he tended to get emotionally invested in patients. Yet, when asked for a list of those patients, she refuses on principle.
Geri's pregnancy is progressing; Carol arrives at the doctor's to learn it's a girl. She gets back in time to witness DI Goodwin scold Ridley for stalking the Flannery funeral; he takes off for the jazz club, where he and Annie discuss if the flowers mean Donnelly's gang is planning to come after him, causing Ridley to remember back when Flannery came to the club over the same concern. The teen throwing slurs at Patrick turns out to be Diane's daughter Rochelle (Olivia Pentelow); She's been harassing him for months after he casually psychoanalyzed her. Rochelle's boyfriend, Jared (Conor Deane), broke into Patrick's flat a few months back at her urging, but the two seem innocent of murder.
Goodwin court orders a list of Patrick's patients since Larsson won't provide it, which includes Cal Flannery. The murderer wore dress clothes; Diane says she saw someone in a suit that night on the estate and identifies Cal. Carol and Ridley's visit to Cal at his late mum's house confirms Patrick died the night of the funeral. Cal is clearly fragile, but Ridley's behavior is over the line. Carol tells Ridley to step away and go home. Instead, he visits Larsson, asking if Cal and Patrick were sexually involved; she insists they were not, though Cal was emotionally attached. Ridley also gets lost in memories of Goodwin, forcing him to reveal Flannery was their Donnelly informant and Flannery blaming him.
When Ridley arrives at the office saying he'd seen Larsson, Carol nearly blows her top; Goodwin pulls him in to tell him he's too close to the case. Diane's picking Cal out of the lineup gives Carol the right to arrest him, but Larsson shows up saying Patrick's diagnosis makes it doubtful he can effectively participate in being questioned. Ridley complains Larsson is just stalling, but Goodwin is clear, Ridley isn't allowed near this. Cal's question goes about as badly as you'd expect. He says Patrick made a pass at him, accuses Ridley of setting him up, and screams that he didn't visit that night before Larsson shuts things down.
On her way out, Ridley stops Larsson and demands to know why she's on Cal's side. She says he's a diagnosed narcissist, but she doesn't think he had it in him to kill Patrick. She also offers Ridley to see her for therapy over his dead wife and child, an offer that hits Ridley with a thought. He asks if she or Patrick recorded their sessions; she said the recording would be at his house if he did. Ridley causally strolls into Patrick's apartment, discovers Dr. Newsome there, and manages to fake casualness enough that she lets him look around. He finds the box with Patrick's voice recorder and SD drives, and steals the baggie.
The recordings include Cal talking to Patrick about Michael being a murderer and the events of the night the Ridley house burned down. Cal makes him switch off the recording before he gets to what Ridley's listening for, but he's convinced Cal helped. He heads back to his old house and remembers his last conversation with Kate and celebrating Donnelly's conviction with Goodwin as, unbeknownst to him, his house burned. Then he heads to see Michael and tells him Cal's locked up before goading him into admitting that Cal set the fire. But Michael won't turn against Cal and walks out.
Ridley heads back to the precinct, where Carol tells him Cal's been released because they couldn't pin anything on him. Ridley freaks, waving the SD drives in front of her, admitting he stole them from evidence, claiming it was because she'd thrown him off the case. He has his own narcissistic fit, screaming how they all need him; everyone needs him to do their dirty work and then betray him. She tells him she will have to report him for stealing the drives; he tells her that they prove Cal killed his wife and daughter, and she better get out there and finds him before he kills again, throws the drives at her, and stalks out.
Michael calls Cal to tell him Ridley knows the truth as Ridley relives watching Michael go down for his brother's crimes. Cal hangs up on Michael; meanwhile, Carol briefs Goodwin and the team at the precinct. As Goodwin comes out to tell Ridley there's an APB out on Cal, but he's off the case and the consultancy until he's ready to return to work, Ridley admits he should have stayed retired. Goodwin says he's sorry for all that led to the fire; Ridley forgives him and reminds Goodwin that he saved his life that night by not letting Ridley run into the burning house.
That's all good; Ridley's list of "things a white dude will do rather than go to therapy" was unmanageable. However, Cal is still out there and is busy destroying Annie's jazz club. Luckily, she's not there, though when she arrives later, she assumes it's Donnelly's gang that did it. (Close, but no.) Ridley tells her they know who did it as he calls for a patrol car to send protection, telling her everything. While he and Annie have a heart-to-heart, Cal breaks into Ridley's house looking for the SD drive. Unfortunately, that's right when Carol's boy Jack, who has been helping Ridley on his boats, turns up to work. Jack walks in, and Cal tries to play it off until Jack pulls out his phone to call the detective.
Carol visits Michael and tells him he needs to help; Michael states the obvious: Cal would have tracked Ridley to his home. This is as Ridley drives back up and sees 1: Cal's car and 2: Jack's bike. Cal hearing Ridley's arrival grabs Jack as hostage. It's all hands heading to the boathouse even before Carol realizes her son is seriously in danger when Geri calls to ask if Carol's heard from him, casually reminding her Jack was going to work on the boat today. Ridley gets Jack out of the house, who starts running like he'd run the whole way back home. Luckily, he doesn't have to; Carol's nearly there. She stops, puts him in her car, and has him debrief her as they drive.
As they arrive with the team, Ridley keeps Cal talking as SCO19 gets in position. Cal handover his gun and begs Ridley to shoot; there's a second bullet Ridley can use on himself. But given a chance for revenge, Ridley refuses; Cal attacks and the gun goes off, hitting Ridley as the snipers take out Cal. Of course, Ridley doesn't die; he says a proper goodbye to his wife before getting up and going to the jazz club, though not before stopping by to see Michael tell him he's being released and promising protection from Donnelly for the rest of his life. Ridley then hits therapy with Dr. Larsson and takes Annie on the boat for their first date. Healing has begun.