Peggy celebrates her birthday on a murder mystery-themed train ride.
- Be Careful What You Wish For: When Hank tells his friends about Peggy's plans for her birthday party, Dale anticipates that it will once again be a disaster. Things do indeed go wrong, and Dale relishes the opportunities to make Peggy feel more miserable (such as calling out the culprit of the planned murder-mystery party after Luanne accidentally spills the beans to her aunt, and reminding everyone there's practically no food after a waitress tells Peggy the refrigeration went out and ruined the birthday dinner and cake). But after everyone gets kicked off the train and Peggy is at her most upset, Dale no longer enjoys it and now genuinely feels sorry for her.
- A Birthday, Not a Break: The crux of the episode is that Peggy's birthdays are notoriously unlucky and always end in disaster. At her last one, the restaurant was robbed, and the crook added insult to injury by blowing out her candles.
- Birthday Episode: Peggy celebrates her birthday twice.
- Bittersweet Ending: The train party is ruined, but Peggy's friends reassure her they love her in spite of her poor birthdays, and they are able to have a good time at a nearby bar.
- Chekhov's Gun: Lucky's love of TV Land mysteries comes in handy when he's able to deduce that Hank and Peggy were the ones who had sex in the bathroom, although he keeps it secret so Peggy can enjoy her birthday.
- Cringe Comedy: Luanne introduces the Manger Babies to make up for ruining the mystery is this, as everybody but Dale hates it.
- From Bad to Worse: Peggy's birthday party on the train starts off pretty well. Then Luanne ruins the mystery by asking about her character, and all of the actors leave in a huff. OK, at least they still have the dinner to look forward to, right? Then the refrigeration goes out and it spoils the prime rib and Peggy's birthday cake, and they're forced to eat crackers and cheese. And because dry Rumphert County is oddly shaped due to election reasons, the train isn't legally allowed to serve any alcohol, and Luanne tries to pass the time by introducing the Manger Babies.
- Get Out!: When the party collapses on the floor, the conductor assumes they're having an orgy and forces them off the train.
- Jerkass: Dale only comes to Peggy's birthday parties because they always go horribly wrong, but he enjoys seeing them go to crap to amuse himself. Hank doesn't even try to stop Dale's toxic behavior.
- Laser-Guided Karma: Dale takes great pride in Peggy having horrible birthdays. When Peggy arranges for a Disco -themed murder-mystery dinner party on a train ride, Dale anticipates it becoming yet another lousy Peggy Hill birthday. When it does happen (due to Luanne accidentally revealing the murder victim before the train even pulls out of the station, the refrigeration going out (and ruining the planned dinner and cake), the train traveling through dry counties (meaning no alcoholic beverages), and Hank and Peggy having sex in the train's restroom leading to Khan trying to match up the couple's feet with the footprints on the mirror), Dale initially enjoys it and tries to fuel Peggy's misery. But when everyone gets kicked off the train (Hank distracted everyone from the mystery by scaring the engineer into stopping the train), Dale notices how upset Peggy really is and starts to genuinely feel sorry for her..."This is Peggy Hill's worst birthday ever. I should feel on top of the world, yet I'm not. I feel strangely hollow inside."
- Making Love in All the Wrong Places: When Peggy is very upset as things at her intended disco murder-mystery party keep going wrong, Hank follows her into the restroom to try and cheer her up. This soon leads to them having sex in said restroom.Hank: (to Peggy after they return to the dining car) Did we just have... relations in a public place?
Peg: (feeling content) Unless this is all a very weird dream, yes, we did. - Out-of-Character Moment: The ever uptight Hank and Peggy end up having sex in the train bathroom, setting off the mystery plot.
- Rail Enthusiast: Dale is revealed to have some knowledge on how trains work. His explanation on the locomotive having a "dead man's brake" comes in handy later on when Hank needs to create a diversion before Khan finds out he and Peggy had sex in the train's restroom, and so Hank sneaks into the locomotive and scares the engineer into stopping the train.
- Serious Business: Hank thinks if he and Peggy are caught, that Strickland Propane will get heavily sanctioned or even forcibly shut down, since the train is under the jurisdiction of the Texas Railroad Commission, which also regulates propane. Perhaps it never occurred to Hank that his boss has likely done way worse in much worse places, and still hasn't gotten sanctioned, or that when the conductor thought the entire party was having group sex, including a propane salesman, he simply forced them off the train.
- Screw This, I'm Outta Here: The actors leave the train when Luanne accidentally spoils the mystery.
- Thriller on the Express: Peggy's birthday plan involves a Studio 54-themed murder-mystery party on board a train, where actors play out the mystery and the passengers try to solve it. Unfortunately, when Luanne is cast as a last-minute replacement for the murder victim, she accidentally reveals the killer to Peg, and when Dale calls out the solution, the actors all leave the train the moment before it departs the station. Fortunately, some time into the trip, Hank cheers up Peggy by having sex with her in a restroom on the train. After they leave, Khan notices the footprints on the restroom mirror and decides to play detective and have everyone go into the restroom to see whose feet match the prints.
- Unwitting Instigator of Doom: Much of the chaos of the episode wouldn't have happened had Luanne not spoiled the mystery.
