Finn, Jake and BMO are having fun river rafting (with Jake as the raft). They are having fun until BMO says it's time for Ice King's book reading. All three go to the reading, although Finn does not want to. At the library, the Ice King is holding a public reading of one of his Fionna and Cake fanfictions. After his reading ends with no applause, the Ice King gets mad at the audience making the audience to clap afterwards. Suddenly, someone comes to the library and says that Ice King's story is wrong, and it is revealed to be an older Fionna. She has a tape with her which reveals the truth.
In a swamp, they find a way in through a door and takes the fancy coffin left there. They bring it into their vault, and a bandaged hand comes out of the coffin. The Ice King urges her to continue the tape, and Fionna agrees.
A mummy comes out of the coffin, but the tape ends there. The Ice King invites her to live with him, and she instantly begins taking charge. He asks her where Cake is, but she says that there was an accident, and she does not want to talk about it.
The tape finishes quickly, and Fionna goes to sleep, but the Ice King steals it from her. He continues watching the tape, which shows that the mummy is truly the Queen of Ooo. The Ice King ends the tape confused, but realizes that the person in his home is not Fionna.
When he confronts her, she reveals herself to be an old lagomorphic humanoid, who had intercepted the signal with the tapes and modeled herself after Fionna. The Ice King exclaims that he feels betrayed, and she realizes that she is no better than the mummy.
Late at night, a red beam comes down from the sky to the Ice King's head, with images of Fionna and Cake.
- Queen of Ooo
- Abracadanielle (flashback; cameo)
- Ruse Goose (flashback; cameo)
- Peppermint Butler
- Banana Guards
- Lumpy Space Princess
- Turtle Princess
- Transformation Ghoul
- This is the second and last Fionna and Cake episode to feature Finn and Jake. The first is in "Fionna and Cake."
- This is the first and only Fionna and Cake episode where the aforementioned characters appear with a minor role (not counting Ice King's imagination in "Mystery Dungeon") albeit shown in a videotape.
- The reveal that the other Fionna is really a humanoid with rabbit-like ears is similar to an original concept for "The Simpsons" which would have revealed Marge Simpson having rabbit ears in her tall hair, which was scrapped for being too surreal.
- Some real-world books and authors are exhibited on the library shelves in this episode, including Edgar Allan Poe, "The Phantom of the Opera," and Goethe's "Die Leiden des jungen Werthers."
- This is the fifth and final episode of the Fionna and Cake saga, following Season 3's "Fionna and Cake," Season 5's "Bad Little Boy," Season 6's "The Prince Who Wanted Everything," and Season 7's "Five Short Tables."
- Cake uses Key Eye, her special technique to open doors, which is similar to Jake's Key Hand seen in "Prisoners of Love" and "Dungeon."
- Ice King has a box of Drop Ball balls in his closet, which reference the episode "Blood Under the Skin."
- The "stuff" section of books shows up in this episode, a reference to the episode "Blank-Eyed Girl."
- This episode also mentions Ice King's Tapes, which were introduced in "Holly Jolly Secrets part 1 and 2"
- It is unclear where the Fionna and Cake video came from. Other Fionna claims that she received a mysterious signal on her TV, but this is all the knowledge she had to offer. One of Ice King's lines, as well as the end of the episode, show that the Fionna and Cake stories are projected into Ice King's mind from a beam of red light in the middle of the night: However, said beam's origins are unknown.
- It could be that Other Fionna somehow (accidentally) intercepted the beam of red light that one night, catching the 'broadcast' on her tape.
- Other Fionna states that Fionna and Cake aren't real and that they're just a T.V. show from the past. It is known that Simon used to watch pre-mushroom war television because in "Simon & Marcy" he referenced Cheers by singing "Where Everybody Knows Your Name".
- In "Five Short Tables" Ice King completes five separate stories with a theme at the end. This is similar to the way that Cuber tells stories with a theme in "Five Short Graybles." However, this happens in Ooo's future long after Ice King has reverted back to Simon. There is no explicit evidence that Cuber took inspiration from Ice King's storytelling style, so it is reasonable to conclude that both structured their storytelling styles independently.
- This episode was released early on the Cartoon Network app on July 14, 2017.
- When Fionna and Ice King are exiting the library, the same bookshelf sequence scrolls by twice in the background, including "The Moon and Six Pence," "History of Mystery," and a skull.