Monk takes on a case for a couple whose daughter was murdered. The culprits, according to the lone witness, were a local cult called the Siblings of the Sun. Monk goes undercover as a recruit to investigate the matter from inside the cult, but falls victim to "Father's" mind tricks. Will Monk ever return to his old, neurotic, crime-solving self?
This episode includes examples of the following tropes:
- Absence of Evidence: Monk proves that the picture of Amanda Clarke and Tom Donovan wasn't taken while he was rushing her to the hospital, as he claimed; there wasn't any blood on the seatbelt, which was clearly visible in the picture.
- Alliterative Name: The cult leader's name is Ralph Roberts.
- Becoming the Mask: Monk goes undercover as a member of Siblings of the Sun, only to buy into their teaching to the point that Stottlemeyer and Natalie have to "kidnap" him so he'll snap out of it.
- Big Secret: It turns out that "Father" did have an alibi for the night of the murder; he was in his cabin, receiving a cortisone shot from his doctor. He couldn't reveal this because part of his image is never being sick.
- Bitch in Sheep's Clothing: The Good Samaritan that supposedly helped Amanda get to the hospital? He is in fact her killer; he was just framing the Siblings of the Sun.
- Chekhov's Gun: The beeper.
- Church of Happyology: The Siblings of the Sun, complete with a "free personality test" reminiscent of Scientology's infamous "free stress tests".
- Comically Missing the Point: When told Amanda worked "the world's oldest profession", Monk figures he knows what that means: stonemasonry.
- Cult: The Siblings of the Sun, if the episode's title somehow didn't give that away.
- Cult Defector: The Victim of the Week ran away from a Church of Happyology and became a prostitute due to how messed up the experience left her. She spent the rest of her life living in fear that they'd kill her for leaving the cult, but the cult is a Red Herring.
- A Deadly Affair: Tom has apparently been hiring Amanda for her services for some time, and he killed her so as not to explain what she was doing in a company car with him.
- Department of Redundancy Department: Monk at one point refers to Amanda as a "Sex Prostitute." As opposed to all those other kinds of prostitutes.
- Disposable Sex Worker: When he realized he had been caught with Amanda in his company car, Tom decided her services would no longer be required.
- Hypocrite: Dr. Kroger, while attempting to deprogram Monk, tells him that "Father" owns property all over the place, despite saying that money causes envy and envy is the wellspring of evil.
- I Have No Son!: The other cult members considered Amanda Clark dead from the moment she left the cult.
- I Resemble That Remark!: Monk contests Stottlemeyer saying he's gullible, and Stottlemeyer says that it's not just his opinion; it was Joey Heatherton's when he spoke with her. Monk asks if he really did, thus proving the Captain's point.
- Jerkass Has a Point: “Father” is right that Monk uses his hand wipes and other Character Tics as crutches to avoid confronting his problems, and is even able to successfully help him overcome much of his paranoia and neuroticism. Unfortunately, Father packages this advice with standard cult brainwashing and cons Monk out of his savings.
- Kidnapped by an Ally: Natalie and Stottlemeyer drag Monk into a car and hold him "hostage" in an attempt to break the brainwashing. He's eventually happy about it.
- Morality Chain Beyond the Grave: Dr. Kroger brings out a picture of Trudy and wonders to Monk what she would think if she saw Adrian under the cult's influence. When Monk brushes it off, Dr. Kroger responds that they have no need of the picture, and crumples it to call his bluff. Monk begins to come to his senses, picks up the picture, and begins crying. Dr. Kroger takes this as a sign that he's back.
- Murder Is the Best Solution: Surely Tom Donovan could have thought of an explanation for why he had a strange woman in his car in the middle of the night that required a bit less homicide.
- O.O.C. Is Serious Business: During the intervention, Natalie offers to get Monk a wipe to clean food that he's refused off his face. He shocks her by wiping it on his sleeve.
- Outliving One's Offspring: Mr. and Mrs. Clark outlived their daughter, Amanda, who was murdered.
- Revealing Cover Up: Tom Donnavan killed Amanda to cover up his affair with her. He ran a red light while driving her around in a Company Car, so the ticket would have been sent to the office where his wife would have seen the picture of him in the car with a strange woman. So he stabbed Amanda, drove her to the hospital (thus creating a cover story for why the picture exists), and then tried to pin her murder on Father.
- Super Gullible: Stottlemeyer protests Monk's idea to go undercover with the Siblings of the Sun because of how gullible he is and how expert "Father" is at brainwashing people. He mentions that it's not just his opinion: Joey Heatherton also thinks Monk is gullible, and Monk is overjoyed she knows him.
