The episode juxtaposes between Halloween of four different years—1993, 2004, 2009, and 2018.
Mr. Peanutbutter is inside the closet of his new home, dressed as a hippie. He goes outside where his wife Katrina, who's dressed as Blossom, is very cheerful and happily married to him. Katrina is excited to got to a real Hollywood party with him, but she makes him promise he won't leave her alone.
They arrive at BoJack's house. He has no idea who they are or what they're doing here. Mr. Peanutbutter says he invited him to his Halloween party, but he told him he couldn't because he was having one of his own—so Mr. Peanutbutter brought his party to BoJack's, much to his annoyance.
As he tries to control the party guests, BoJack assigns Marv's new assistant, Princess Carolyn, to door duty. She takes this job with excitement and asks if he has any candy to give Trick-or-Treaters. He gives her the year's Emmy screeners.
BoJack notices that the punch has been spiked, but he decides one drink won't hurt. Mr. Peanutbutter is on the couch talking with two actors from The X-Files, asking what happened to files A-W, when Katrina arrives. She's upset he left her alone when she went to use the bathroom.
Mr. Peanutbutter apologizes and says he got distracted by the fun party. He assures her he won't leave her again, but he goes to talk to Erica, with the excuse she can't talk to two people at once because of her split-brain surgery.
Katrina stands alone on BoJack's deck. Mr. Peanutbutter jumps out of the pool and goes to talk to her, saying the conga line leader led them all into the pool. An annoyed Katrina tells him she wants to leave, saying she's not having fun because she doesn't know anyone at the party, but instead Mr. Peanutbutter makes her talk to BoJack, who leaves her too after realizing he needs a Halloween costume.
Princess Carolyn puts a lampshade on BoJack's head and tells him he's a "one night stand." He thinks it's hilarious and tells her she should be a producer, but she just laughs this off.
Mr. Peanutbutter goes back to Katrina, telling her he got distracted by some guys with an Ouija board. A bitter Katrina tells him while he was gone, Ben Stein introduced her to Tim Allen. They talked for ten minutes about how the government is using their money. She brings up that now that they are in a new tax bracket, maybe they should pay attention more to how the government is using their money.
Mr. Peanutbutter is shocked that she learned all this from talking to Tim Allen for ten minutes, but Katrina angrily says he left her alone for an hour and a half. Mr. Peanutbutter guesses time flies when you're having fun. Katrina snaps and angrily shouts "I AM NOT HAVING FUN," which interrupts the party.
Katrina yells at Mr. Peanutbutter for leaving her alone. She says she asked one thing from him, and he never listens. Mr. Peanutbutter assures her he'll never leave her alone again, but Katrina storms off saying she wants to be alone now and tells him to have fun with his hippie liberal friends.
Everyone leaves as Princess Carolyn says that the party is over. A drunk BoJack tells everyone to make this party an annual thing, and he wants to see everyone back here next year.
Mr. Peanutbutter exits his closet dressed as a notebook. His wife, Jessica Biel, tells him she meant the movie The Notebook, as she's dressed like Rachel McAdam's character, Allie Hamilton, from the movie. She's not too bothered by this, because they'll still look cute together.
Mr. Peanutbutter says anytime he went to a Halloween party with Katrina, they always got in a big fight, but Jessica tells him she isn't Katrina, and they'll have fun. However, she tells him to keep her away from any mummies due to a traumatic incident from her past.
They arrive at BoJack's house. BoJack, annoyed, questions what they're doing here. Mr. Peanutbutter says that they're here for the Halloween party that he's had for the last eleven years, as BoJack always says at the end of the parties to do it again next year.
Princess Carolyn answers the door to find three teenage Trick-or-Treaters. She refuses to give them candy because they are too old to be trick or treating. One of the kids pushes up his mask in protest and is revealed to be a young Todd. Because Princess Carolyn doesn't give them any candy, thirteen-year-old Todd, Emily and a friend of theirs teepee BoJack's house.
Mr. Peanutbutter asks Jessica why she's afraid of Mummies. She says it's because she auditioned for The Mummy movie for the role of the mummy with Brendan Fraser...and didn't get the part.
BoJack doesn't have a costume so asks Princess Carolyn for help. She takes him outside and uses the toilet paper to turn him into a mummy. He approaches Jessica Biel while Mr. Peanutbutter watches in dismay. He tries to get to her before she can see BoJack but fails.
Jessica yells at Mr. Peanutbutter for not keeping the mummy away, while also revealing she auditioned to play the actual mummy as she storms off.
Mr. Peanutbutter is getting ready to go to BoJack's Halloween party with his girlfriend, Diane. He's dressed as the guy from the first, at the time only, Hangover movie, and Diane is "Baby Bjorn Borg” (a cyborg, tennis player Björn Borg, and the Baby Bjorn from The Hangover). Mr. Peanutbutter tells Diane anytime he went to a Halloween party with one of his wives they would get in a huge argument, so he's glad she's so fun and easygoing and loves parties.
Princess Carolyn answers the door, and this time allows Todd (now eighteen) to come into the party. He compliments the house, and Princess Carolyn says it's her boyfriend's. Todd questions why her boyfriend makes her answer the door.
Princess Carolyn begins to deny this but suddenly has an epiphany, questioning what she's doing with her life, and saying she came to L.A. when she was eighteen and is already thirty-five. She rushes out the door and passes the box of screeners to Todd, leaving him with the responsibility.
BoJack then pours alcohol into the apple cider, saying if he's gonna be trapped with "all you losers" he may as well get drunk.
Diane is upset because she has to explain her costume to everyone over and over. Mr. Peanutbutter asks if she wants to leave, but she says no, insisting she's fun.
Later, Diane asks if they can go soon, because being around so many famous people is making her nervous. Mr. Peanutbutter instead encourages her to go talk to BoJack, who just got a phone call from his mother, and is asking if it could wait.
BoJack is still on the phone with his mom. He's saying to her "What do you mean, a duel? You mean like, like a duel, a duel?" After seeing Diane, he puts his mom on hold.
He immediately guesses what Diane's costume too, and in an annoyed tone asks what she wants. Diane nervously rambles about how she loved Horsin’ Around and how the show played a huge role in her formative years. She nervously sings the theme song. BoJack tells her he's on the phone, and Diane timidly apologizes and walks away. BoJack gets back on the phone with his mom and says it was no one important.
Mr. Peanutbutter is on BoJack's couch talking to two actors from Glee, asking why they also sing when they're not in glee club. An upset Diane tells Mr. Peanutbutter she made a fool of herself in front of BoJack, and questions why he made her talk to him. Diane says she's good in small groups and shouts that she hates parties, which interrupts the party.
She tells him it's too much pressure to try to be as fun as his ex-wives, and she runs out of the house.
The party has ended. BoJack hangs up with his mom but promises to help figure out what they're going to do for his dad's funeral, and genuinely tells her he's sorry. He goes back into the house to learn from Todd that the party is over. BoJack laments that he thought he would feel something when this (one of his parents dying) happened, but he doesn't. Todd offers to stick around for a bit, and BoJack agrees and tells him to stick around as long as he wants.
In their car, Diane apologizes to Mr. Peanutbutter for ruining another Halloween for him. Mr. Peanutbutter says she didn't, and that he loves her and wants to know the real her. He's glad he knows she hates parties and they won't ever have that argument ever again. Diane is still upset about BoJack, but Mr. Peanutbutter assures her that he won't even remember that he met her.
Mr. Peanutbutter and his girlfriend, Pickles, are getting ready for BoJack's twenty-fifth Halloween party. They are wearing matching costumes inspired by a new social media app called "Tweed Feed," which are tweed outfits with dinner plates, silverware, and plastic food taped to them. Pickles is excited to go to her first fancy Hollywoo party.
BoJack answers the doorbell, and to his utter dismay finds Mr. Peanutbutter and Pickles, and a crowd of party guests lined up behind them. They all barge in. BoJack laments to Gina how he always lets these parties happen because he takes no action to stop them. Gina feels dumb for not wearing a costume and says she's going to Rite Aid to get one. She tells BoJack to not let the party die before she gets back.
Diane arrives in her car, but groans, having forgotten about the Halloween party.
Princess Carolyn answers the door and Diane walks in. Diane says that she hates Halloween and is just here to drop off pages for BoJack. Princess Carolyn laments about being on door duty again.
A drunk BoJack is sitting with Mr. Peanutbutter and Pickles. He asks them if they remember the time one woman freaked out because she saw a mummy. Mr. Peanutbutter says that was his ex-wife, Jessica Biel.
BoJack comments he's brought so many ex-wives and girlfriends over the years it's hard to keep track, a comment that Pickles doesn't seem to appreciate. He excuses himself to go run the costume contest. Mr. Peanutbutter tells Pickles he can't believe that they've been having this party since 1993, to which Pickles exclaims that was the year she was born.
Diane wants to leave but is her car is trapped between two vehicles. Todd says that one of those vehicles is his car. He explains it's the company car, and it matches his hat. He tosses her the keys and tells her to take it for a spin.
A drunk Pickles goes up to Diane and tells Diane that it's okay if she's jealous because she's definitely not jealous of her. Diane says she isn't jealous either and leaves. Mr. Peanutbutter tells Pickles that that's just Diane and that she's no fun. Pickles is getting annoyed he keeps bringing up all his ex-wives. Mr. Peanutbutter then realizes that all of his ex's used to be fun, but turned bitter and cruel after being with him but can't figure out the common denominator.
Diane returns and is now looking for the owner of a blue Tesla. She runs into BoJack, and the two are tense around each other now due to the submarine scene Diane wrote for BoJack in the previous episode. BoJack brings this up but denies to Diane he wants to talk about it. When she walks away, he swallows a couple of his painkillers for his back and says this party sucks.
Pickles is dancing on the coffee table when Mr. Peanutbutter comes to apologize for talking about his ex-wives. She cheerfully says it's fine, but starts to sound upset when she talks about his ex-wives and how Diane is here.
Diane, who now has a bunch of car keys, is still trying to get her car out and calling people to move their cars. Mr. Peanutbutter tells Pickles they should leave. Pickles tearfully shouts at him that she is having fun, which interrupts the party. She runs off crying.
Mr. Peanutbutter is standing outside the bathroom, trying to get Pickles to come out. Diane walks up to him and asks what happened. He tells Diane that he keeps taking amazing women and ruining them. Diane says that she isn't ruined, and he says that his problem is that he doesn't listen.
She says that he keeps dating women in their twenties, so they aren't fully formed yet—he doesn't ruin them they just grow up. Mr. Peanutbutter asks how he should fix that. Diane says he either needs to date older woman or grow up himself, or his girlfriends will keep outgrowing him. She walks into the bathroom to talk to Pickles.
Pickles is hungover and sitting in the bathtub. Diane gives her some water and tells her she understands that it's hard to be the new girlfriend. Pickles wonders if she's a rebound. Diane says that she was a rebound, but Mr. Peanutbutter loved her unconditionally for ten years.
She tells Pickles Mr. Peanutbutter is fully devoted to whoever he is in a serious romantic relationship with and she tells Pickles that she's that girl now. Pickles reconciles with Mr. Peanutbutter, and Diane leaves, saying she's gonna take someone's helicopter home-seeing that she is unable to reach her car.
Mr. Peanutbutter suggests to Pickles they go home, but Pickles wants to go to another party after they go home and change costumes. She takes a selfie with Mr. Peanutbutter and happily exclaims that she never wants to grow up. Mr. Peanutbutter laughs nervously at this.
Everyone leaves just as Gina finally returns with an elaborate witch's costume she made from random objects. To her annoyance, the party's over and BoJack is passed out on the table. A groggy BoJack announces to have the party again next year. Gina says she's going to bed. BoJack groggily says he loves Halloween.
|Will Arnett||BoJack Horseman|
|Amy Sedaris||Princess Carolyn|
|Aaron Paul||Todd Chavez|
|Alison Brie||Diane Nguyen|
|Paul F. Tompkins||Mr. Peanutbutter|
- In real life, Jessica Biel was one of the actresses considered for the role of Allie in The Notebook, who Jessica is dressed as for Halloween in 2004.
- Pickles reveals her last name is "Aplenty," and that she was born in 1993, making her 25 years old.
- Princess Carolyn dresses as a pilot every year for Halloween, likely inspired by her favorite movie as a child, The Amelia Earhart Story.
- Many costumes reference movies from the time period the characters wear them in or are a running gag.
- A cockroach wears a Beetlejuice costume every year
- A moth always dresses as a ghost, although each year he eats a bit of his sheet until he finishes up at the end of the episode in 2018.
- Jorge Garcia, who played Hurley on Lost, is dressed as Shrek
- A woman is dressed as Mrs. Incredible from The Incredibles
- A woman is dressed in a torn green top and loin cloth and carries a volleyball with a face on it, referencing Cast Away.
- A man is wearing rabbit ears and a basketball jersey that reads "Space Jelly," both of which reference Bugs Bunny and the Looney Toons Movie Space Jam.
- A lemur is wearing a t-shirt that reads "Vote For Tina" referencing Napoleon Dynamite and the llama in the movie named Tina
- A Yorkie is dressed as Captain Jack Sparrow from Pirates of the Caribbean.
- A llama is dressed similarly to Batman
- Two girls and a cat are dressed as The Plastics: Regina George, Gretchen Weiners, and Karen Smith from Mean Girls
- An octopus dresses as the Octomom by attaching baby dolls to her body
- A cat is dressed as keyboard cat.
- Debra is dressed as a sorceress
- Pinky is wearing a "Will Publish for FOOD" sign as Will Work For Food Loafer in Interstate 60. He won the costume contest, but then it turned out he'd just lost all his belongings in a fire, and those clothes were all that he owned
- A running gag, which is seen in 1993, 2004, and 2009, includes Mr. Peanutbutter talking to actors from TV shows famous at the time.
- In 1993, he talks to two actors from The X Files, David Duchovny, who played Fox Mulder, and Gillian Anderson, who played Dana Scully. He asks them about what happened to files A-W.
- In 2004, he talks to Jorge Garcia, who played Hurley on Lost, asking him about the plot of his show.
- In 2009, he talks to two actors from Glee, Lea Michele, who played Rachel Berry, and Chris Colfer, who played Kurt Hummel. He asks them why the glee kids also sing when they're not in Glee Club.
- The Celebrity Stealing Club makes a cameo appearance at the 2018 party, stealing a painting from BoJack's house.
- BoJack's species and the show's name are back to normal from the previous episode.
- Mr. Peanutbutter appears dressed as his character from Philbert at the beginning of the party scene. He still wears his usual V-neck after BoJack falls into the pool.