The season to be jolly becomes a lot less so when the department's Christmas party is interrupted by the death of Detective Terry Chasen, who drank from a bottle of poisoned port. Stottlemeyer, thinking the poison was meant for him, begins fixating on a suspect named Frank Prager, who has reason to hate Stottlemeyer for shooting his brother after a bank robbery. Can Monk get past the difficulties of the investigation to discover the real culprit?
This episode includes examples of the following tropes:
- Artistic License – Chemistry: Disher, while explaining that the poison was strychnine, says that anyone could have made it. Strychnine is actually notoriously difficult for chemists to create. However, it is pretty easy to extract from things like rat or gopher poison.
- Artistic License – History: San Franciscans older than 40 might get a chuckle when Monk says that the last time it snowed in San Francisco was the same day that Trudy died. Continuity states that Trudy was killed on December 14, 1997. As of the episode's original airdate, the last time the city of San Francisco received measurable snowfall was February 5th, 1976.
- Artistic License – Law Enforcement: Alice's police uniform shirt has two chevron stripes, marking her as a corporal. The SFPD doesn't use that rank.
- Batman Gambit: Alice Westergren starts a Secret Santa exchange and arranges for Captain Stottlemeyer to get the victim's name. Then she delivers a bottle of port (which she knows Stottlemeyer hates) anonymously to the captain making it look like a local body shop sent it. Then Alice steals Stottlemeyer's intended gift to the victim and recommends re-gifting the port to him in a pinch, which the captain does. The victim drinks it and is poisoned, making it look like a failed attempt on Stottlemeyer's life and sending the department after the completely wrong set of suspects. Only Monk realizes that the suspect isn't the killer because he passed up a much better opportunity to kill the captain months ago.
- Blood from the Mouth: A trickle of blood runs from Terry's mouth after he drinks the poisoned port.
- Bullet Hole Spelling: The characters investigate a threat on Stottlemeyer's life. The main suspect is a man whose brother was killed by Stottlemeyer and later shot at him as well. It later turns out that he wasn't intending to kill him, just remind him of his late brother by spelling out his brother's first initial with bullet holes. However, he does such a poor job of that, even the highly deductive Monk can't figure out he was doing that until it's pointed out to him.
- But for Me, It Was Tuesday: Invoked and averted. Frank Prager fired at Stottlemeyer and spelled out an "M" for his little brother's name, because he thought Stottlemeyer forgot about killing him and just chalked him off as another worthless criminal. Stottlemeyer is both angry and hurt:Leland Stottlemeyer: Wait... you think I don't think about your brother? I think about your brother every damn day of my life. It was him or me, and it still eats me up inside. I don't need an "M" on a wall to remind me of something like that. No cop does.
- Christmas Carolers: One of Monk and Natalie’s tactics for talking to Prager’s family is posing as a pair of carolers.
- Continuity Nod: Monk, playing Santa, is delighted when one boy asks for a rock polisher, remembering Benjy's disappointment with receiving one as a birthday gift.
- Cringe Comedy: Monk posing as Santa Claus to get near Prager's daughter is a long string of awkward moments.
- A Deadly Affair: Sort of. Terry Chasen had separated from his wife when he and Alice went out, but him going back to his wife lead Alice to murder him.
- Encouraged Regifting: This is how Alice kills Terry. She arranges for Stottlemeyer to be Terry's Secret Santa. Then she anonymously gifts Stottlemeyer a bottle of port, knowing he hates it. She steals the gift Stottlemeyer was planning to give Terry and suggests that he give the port instead.
- Failed a Spot Check: Randy is proud about the homemade sweater that his aunt supposedly made for him. Then Natalie shows him a fellow officer who's wearing the same sweater, and she further points out that Randy's sweater still had its price tag on it.
- Foreshadowing: Monk notes that Frank Prager used to be in special ops and therefore shouldn't have missed five shots at Stottlemeyer, which is an early hint that he wasn't shooting at him.
- Forgiveness: Sister Heather comes out to talk to Stottlemeyer to convince him not to rough Frank Prager up when arresting him and tells him she learned from God that forgiveness is the most total revenge. Stottlemeyer appears to have taken some of this to heart because while Frank will still have to face trial for shooting at him, he lets Frank go on his own recognizance for a couple of days so he can spend Christmas with his family.
- Graceful Loser: When Stottlemeyer, Monk, and a few others confront Corporal Westergren about killing Terry Chasen, she doesn't attempt to run or put up a fight and calmly confesses.
- Hidden Depths: It turns out Stottlemeyer plays the guitar and sings very well.
- Hypocrite: When she's discovered as Chasen's murderer, Westergren says "I just couldn't live without him" even though she did kill him.
- If I Can't Have You…: Chasen broke up with Alice, intending to return to his wife. Furious at the decision, she decided that if she wouldn't be spending Christmas with her ex-boyfriend, no one else would.
- "I Know What We Can Do" Cut: Natalie is going stir-crazy on a stake-out and suggests the go knock on the door. Monk asks what they're going to say, and the scene cuts to Natalie and Monk posing as carolers.
- Innocuously Important Episode: While the main story is a standard case of the week, the episode also introduces the last gift Trudy left for Adrian, which after a few more mentions in later episodes ends up playing a major role come the series finale.
- Ironic Nursery Rhyme: Terry Chasen dies from the strychnine to the Christmas carol "Silent Night", succumbing right at the lyric "sleep in heavenly peace".
- It Began with a Twist of Fate: Double-subverted. At first it appears that Terry Chasen is the unfortunate, accidental victim of a plot to kill Stottlemeyer that went awry thanks to his dislike of port, but it later turns out that the whole thing was meticulously planned by his ex-lover. It ends up being another two chance occurrences that derail her plan, firstly her ending up with Monk as her Secret Santa recipient (which there's almost no way she'd have done on purpose), and then her mixing up the envelope for the card that came with the poisoned wine with the one from the card she gave to Monk, who ends up figuring out she's the killer when he makes the connection.
- Killer Cop: When Chasen decides to break off his affair with Alice and return to his wife, she becomes furious and devises a plan to kill him with a poisoned bottle of port and cast Stottlemeyer as the intended victim. First, she suggests a Secret Santa gift exchange for the department Christmas party, then rigs the drawing so that Stottlemeyer gets Chasen's name. Next, she poisons the bottle, addresses it to Stottlemeyer, and anonymously drops it off at the station. During the party, she sneaks into his office and steals the gift he had bought for Chasen. Knowing that Stottlemeyer hates port, she suggests that he give it to Chasen instead — and the stage is set.
- Mall Santa: Monk and Natalie go undercover at a shopping mall trying to locate the person Stottlemeyer suspects tried to kill him. To do so, this involves Monk being disguised as a Mall Santa, with Natalie wearing a wig to pose as his elf. Although the humor revolved around Monk's obsessive compulsive disorder and having to be up close to children.
- Noodle Incident: When splitting up into teams for the investigation, Randy for some reason was very reluctant to have a certain fellow cop join him, and only had to concede under Stottlemeyer's orders.
- O.O.C. Is Serious Business: Normally Stottlemeyer finds Randy's singing annoying. When Randy joins in on him singing "O Holy Night," however, Stottlemeyer gives him a sweet smile and finishes the song.
- Prolonged Prologue: Unusual for the series, the episode takes a while focusing on preparing for the Christmas party and the party itself before the murder plot actually begins.
- Secret Santa: Stottlemeyer can't find the gift he bought for Det. Terry Chasen, whose name he drew, so he regifts a bottle of port someone had sent him. Then the bottle turns out to be poisoned...
- Shout-Out: The auto shop the wine "came from", one meant for a San Francisco cop, is Eastwood Auto.
- Shown Their Work: One reviewer observed that the episode accurately portrayed the effects of strychnine poisoning.
- Smokescreen Crime: Terry Chasen dies from drinking a bottle of poisoned wine which was supposedly meant for Stottlemeyer. However, Terry was the true target all along.
- Snow Means Death: Monk claims that the last time it snowed in San Francisco was when Trudy died.
- Survivor Guilt: Stottlemeyer is naturally devastated that the poisoned bottle of port that he lent to Terry Chasen was meant for himself. It's lessened a bit when Monk discovers that Chasen had been the actual target.
- Sympathy for the Devil: During Alice's Villainous Breakdown, no one is mad at her for the murder and thinking Stottlemeyer's life was in danger. In fact, Monk admits that he's impressed with her genius. When she admits she was heartbroken over Terry leaving her for his wife, Monk is saddened.
- Tampering with Food and Drink: The killer kills Terry Chasen by injecting a bottle of wine with strychnine.
- Tragic Villain: Alic may have killed a good cop and a father of two. But when it comes down to why she did it, she soberly admits that more than anything, she was unhappy that she would be celebrating Christmas alone...
- Villainous Breakdown: When she's found out over a simple mistake (mixing up the Christmas cards) Westergren maintains composure at first, calmly removing cookies from the oven. But gradually she spirals into a fit of disbelief and frustration at her mistake.
- You Killed My Father: Stottlemeyer thinks that the bottle was sent by Frank Prager. He shot and killed Frank's brother, Michael, while on the job and thinks Frank wants revenge.
