It's Diane's birthday and Mr. Peanutbutter planned the perfect day for her, until they both reach home and discover he's thrown her a surprise party. After a while, she gets into an argument about whether or not Tony Curtis was dead and all of their guests leave.
Princess Carolyn drives Todd home only see "Vincent" without his usual garb and being accompanied by a woman. She immediately concludes that Vincent has a secret family and the kid she saw was his son. She breaks it off later that night. BoJack is worried that he rushed things to soon with Wanda and crashes into a deer as a result.
Diane and Mr. Peanutbutter argue over what happened and Mister Peanutbutter reveals that he was scared of Diane leaving him for a dangerous, war-torn country.
"After the Party" contains examples of:
- Art Shift: Wanda's jokes are illustrated in the style of a children's book.
- Brick Joke:
- Sir Paul McCartney being baked into a cake.
- Wanda tells BoJack a joke about a gardener who knows exactly how much mulch he needs for a job. He overestimates and the extra bag of mulch drives him crazy, so he tosses it out on the freeway. BoJack doesn't understand how this is a joke and Wanda says he'll get it later. She then tells him another story of a woman who sent old love letters to her ex-boyfriend. Her current boyfriend gets paranoid and jealous. He drives her to her home near the freeway, but forgets to close his window. When he comes back, he discovers a bag of mulch in his back seat.
- Driven to Suicide: It's implied that Princess Carolyn's phone blacking out upon Todd's phone rebooting is this.
- Furry Reminder: Wanda could both fly and see great ranges in the dark.
- It Makes Just As Much Sense In Context: Todd and Princess Carolyn's phones fall in love.
- Running Gag: Once again, Mr. Peanutbutter has difficulty translating what he says into text."I HAD A BALL AT DIANE'S 35th BIRTHDAY AND UNDERLINE BALL I DON'T KNOW WHY THIS IS SO HARD"