A change in Monk's insurance policy means the end of his private sessions with Dr. Bell. In desperation, Monk joins a therapy group and stumbles on murder. Members of the group have died suspiciously close to one another. Monk attempts to solve the case while coping with the change — and particularly with Harold Krenshaw, who has made an unwanted reappearance.
This episode includes examples of the following tropes:
- Absence of Evidence: Monk was able to realize the first woman was killed when she was found drowned in the pool, because there was no towel by the pool.
- Acquitted Too Late: Monk is investigating Rhonda, a somewhat aggressive member of his therapy group, to see if she could be the killer when he finds her on the floor of her workplace, dead of chlorine gas poisoning.
- Borrowed Catchphrase: Harold Krenshaw borrows a couple of phrases Monk usually says when laying out his theory about Monk being the murderer.
- Bread, Eggs, Breaded Eggs: Monk tries to squeeze as much therapy out of his last free session with Dr. Bell as possible by bringing cards with all of his problems on them. When he says "fear of bees," Dr. Bell reassures him that an urban environment makes it a minor fear. "Fear of blenders" is met with the point that one who does not own a blender needn't fear them. "Fear of bees in blenders" just merits a stunned look from Dr. Bell.
- Call-Back: When Natalie is trying to convince Monk he couldn't have been the killer, he brings up that he sometimes has blackouts, which has happened before in the show.
- Censor Suds: At the beginning of the episode, the soon-to-be-murdered Barbara O'Keefe is taking a bubble bath and (this being a basic cable show) the bubbles prevent the audience from seeing her naughty bits. She then puts on a Modesty Towel before being confronted by her killer.
- Chekhov's Gun: Natalie mentions a drought early in the episode. This turns out to be part of the reason behind the murders — the killer murdered a woman and sunk her car (with her body in the trunk) in the reservoir. He was afraid it would be discovered soon and wanted to get rid of the people who could tell the police about his obsession with her.
- Chekhov's Gunman: Harold Krenshaw points out a former patient at the grocery store. He turns out to be the killer.
- A Day in the Limelight: Dr. Bell gets the spotlight in this episode.
- Empty Chair Memorial: When Monk has his first group therapy session with Dr. Bell, he notices an empty seat and learns when one of the other clients gets mad at his trying to take it that it belonged to a young woman who used to be in the sessions until she apparently drowned in her swimming pool. That death is later proven to be murder.
- Fire-Forged Friends: Monk and Harold Krenshaw actually become friends after being locked in a car trunk by the killer and having to overcome their claustrophobia together.
- Heel–Face Turn: Downplayed; after years as Monk's Sitcom Arch-Nemesis Harold realizes that the two are a lot alike and becomes his friend. Then he makes a un-Krenshaw gesture and joins a new group therapy to allow Monk to have Dr. Bell to himself (Though his insurance required him to be in group therapy, the other members were murdered by the bad guy leaving only Harold and Monk so Harold leaving left Monk as the only member remaining).
- He Knows Too Much: The reason behind the murders; some time back, a former member of the therapy group, Xavier Danko, was a part of the group due to his obsession with an exotic dancer named Tiffany Bolt. It was assumed Danko left the group because he had gotten over said obsession, but in reality, he had killed Tiffany, stored the body in the trunk of her car, and dumped it into the reservoir. Now due to a drought, the body was likely to be discovered soon, and the people in the therapy group had heard him talk about his obsession with the woman he murdered. He wanted to get rid of them so the police couldn't connect him to her death.
- Hoist Hero over Head: In Harold Krenshaw's summation about how Monk committed the murders, he lifts Augie over his head before throwing him off the roof. Augie was a plus-size guy, which makes the situation unlikely.
- Imagine Spot: When Harold makes his own The Summation of Monk being the culprit.
- Insane Troll Logic: Randy concludes that the killer is killing people based on their phobias when they find Augie dead from a high fall. When informed he was afraid of spiders, not heights, he switches to saying the killer kills with the opposite of the victim's phobia. When the logic of how the opposite of a spider being a tall building is questioned by Stottlemeyer, Randy doubles down, which is so ridiculous it makes Leland tear up a little.
- Loophole Abuse: Monk's insurance will not pay for any more one-on-one therapy sessions, but he is allowed to have group sessions. By the end of the episode, he’s the only person left in the group sessions, meaning they’re technically still group sessions but with only one person.
- Make It Look Like an Accident: Monk discusses how Rhonda's death could not have been an accident, because, having had this job for years, she would have known better than to mix bleach and ammonia.
- My God, What Have I Done?: One of the few episodes with a killer who regrets what they have done, though it is played for laughs when Monk interrupts their moment of guilt.
- Offscreen Moment of Awesome: The killer goes to Dr. Bell's house with a gun in order to kill him. In the time it takes Monk to get there and save the day, Bell has already talked him down and convinced him to give himself up to the police.
- Plot Hole: Harold theorizes that Monk is killing off the members of the group so he can monopolize Dr. Bell, and Monk actually wonders if this is true. Neither of them address the question of how he knew to kill Barbara three weeks before he even found out he'd need to switch to group therapy.
- Punk in the Trunk: The killer locks Monk and Harold in the trunk of his car when he drives to Dr. Bell's house.
- Stalker without a Crush: It's implied by his familiarity with both Dr. Bell's address and the police response time to arrive that Harold stalked him to his house.
- The Summation: When Monk tells the rest of the group about the possibility of the deaths being homicides, Harold mimics Monk's investigation style and then goes into a summation-slash-Hannibal Lecture in which he points out that Monk had motive, opportunity, and an advantageous position complete with fake flashbacks that portray Monk as an Ax-Crazy pseudo-Yandere who wants Dr. Bell all to himself (Harold was right about the last part). This is effective enough to make Monk himself seriously consider that he might be unconsciously killing people.
- Theme Serial Killer: Randy suggests the possibility of a serial killer murdering people in accordance with their worst fear. Monk undermines that by saying the victim was afraid of spiders, not heights. Undeterred, Randy suggests there's a serial killer murdering people with the opposite of their worst fear, and dubs him "the Opposite Killer."
