The episode opens with the gate keeper at Castle Lemongrab checking Princess Bubblegum's passport, and Finn on the phone with Jake who is trying to advise him against doing this dinner with Bubblegum because of his recent break-up with Flame Princess. As they are allowed through the gate, they enter a stagecoach that takes them to the castle. When they enter the castle, the Lemon Children have significantly changed in appearance, now wearing fancy clothes and show signs of mild intelligence. One of the Lemon Children is dangling from the ceiling, and announces their arrival, but does not quite get their names right. The Earl of Lemongrab appears, having gained much more weight since the last episode he was in. Lemongrab 2 also appears, but his legs are gone and half his face is bitten off. He follows on a device that lets him hover. Both Finn and Princess Bubblegum are surprised to see the changes in both of the Lemongrabs. The Earl of Lemongrab bends over and welcomes the two. When Lemongrab 2 attempts to welcome them, the Earl stops him. Instead, he instructs Lemon Head to announce that it is dinner time, who does so immediately.
The scene shifts to the dinner table. The Lemon Children enjoy the sophisticated party (in their own weird way), while servants serve lemon-based food. Finn switches places with a Lemon Child named Duke Suck-lemon to sit next to PB. Finn asks how PB is doing, but the Princess responds by telling Finn that something has happened to the two Lemongrabs, and that she is concerned because they used to be identical. The gluttonous first Lemongrab smacks Lemongrab two with a leg of chicken for floating too high on his device, and greedily devours more food. He then orders for a floor show. Finn offers to play in it with his flute, but Lemongrab says that only Lemons are allowed. The show consists of two lemon children, one smacking himself, and another just going "WHA" over and over, which does not please Lemongrab at all. He electrocutes the performers with a remote control button, which makes them do it faster and louder. While the show proceeds, the satisfied Lemongrab takes a Lemon Child's piece of bread, his only food, and eats it. Lemongrab Two, feeling pity, gives some of his bread to the child. Lemongrab is outraged by this, and screams "UNACCEPTABLE" while Lemongrab two murmurs "acceptable..." The two Earls then argue over this. PB says that she cannot watch the brothers fight anymore, so she wanders off.
While wandering around the castle, which seems to be falling apart, she discovers Lemonhope, a talented young Lemon Child singing a song of sorrow with his harp. PB loves the little boy instantly, and says that he can come to the Candy Kingdom with her because Lemonhope says Lemongrab hates him and his music, locking him in a filthy bathroom. Suddenly, both Lemongrabs burst in the door, and Lemongrab smashes Lemonhope's harp. PB says that Lemonhope is a brilliant boy, and should go to her kingdom, but Lemongrab snatches him away. PB schemes of how to free Lemonhope, and, as suggested by Finn, pulls a prank along with Finn on Lemongrab by exploding his pudding during dessert. This gets both PB and Finn stuck in the dungeon with Lemonhope. Lemonhope plays Finn's flute at their urging, but he plays awfully. Suddenly, both Lemongrabs dance into the room, hearing the awful noise as beautiful music. Lemongrab two releases them all, to the utter anger and outrage of Lemongrab. Lemongrab one says that his clone is too soft, and he finally eats his brother whole.
Princess Bubblegum, Lemonhope, and Finn escape, but find that the castle gates are locked. Finn suggests pranking him again, but PB replies angrily that that will not work, and that she is too old for that stuff. Suddenly, Lemongrab appears on a balcony, and orders all of his children to kill all three of them. During the battle, Lemongrab Two forces his way halfway out of his brother's mouth, and yells out to his children:
"It has cost me much...but I have learned..that Lemon need not squeeze lemon to survive. LEMONHOPE! Go forth! Grow strong and return for us! Go!"
As the children all stop attacking, Lemongrab Two then releases all his citizens from their electroshock collars, freeing them from his tyrant brother. Lemongrab One then forces his brother back into his stomach and eats him for good. The Lemon Children help the three heroes over the castle gate, while Lemongrab stares at Lemonhope in hatred.
Jake calls Finn, and Finn suggests that he patches things up with FP, realizing how it feels to be manipulated, and that PB is just too old for him. Jake teases Finn about Flame Princess already having a new boyfriend. Then he laughs at the look on Finn's face and says he was kidding, but quickly adds that she might as the episode ends.
- Princess Bubblegum's passport signature reads "BubbleGum."
- In the bathroom where Lemonhope was imprisoned, the "toilet" is actually a lemon squeezer (reamer).
- A clip of this episode was shown in the Honda Civic "Today is Pretty Great" commercial from 2014.
- In the place of Finn's signature, Kilroy can be seen on Finn's passport when the Lemon Gatekeeper admits Finn and Princess Bubblegum.
- Finn's passport closely resembles an Australian passport.
- 'Big' Lemongrab strongly resembles Baron Harkonnen from the film version of Dune.
- The white Lemongrab's hover chair strongly resembles Yoda's hover chair from the third "Star Wars" movie.
- The title is a reference to "Too Young." Also, many events in this episode also parallel the events of "Too Young."
- Finn uses the phone talking to Jake at the beginning and end of the episode, similar to Jake's pep talk to Finn in "Too Young."
- The way the Lemon Child announced Finn and Princess Bubblegum's arrival was the same way Manfried announced the Earl's arrival.
- After the Lemon Child announced Finn and Princess Bubblegum's arrival, another Lemon Child fell from a trapeze to the ground, much like Cinnamon Bun did after Manfried announced the Earl's arrival.
- Princess Bubblegum notes that the castle has fallen into disrepair since she last saw it, mirroring Lemongrab's opinion that PB's castle was in "unacceptable condition."
- Finn asks Princess Bubblegum if she wants to prank Lemongrab "like old times" similar to how he and younger Princess Bubblegum pranked Lemongrab.
- The way Finn and PB crawl to the counter to place the prank is also similar to the way they did in the former episode.
- Lemongrab says that Princess Bubblegum is too old for pranks at the last part of the episode.
- Lemongrab still has his glasses for his farsightedness from "Too Young."
- The title card music and music when PB and Finn prepare the prank is also the same from "Too Young."
- Finn still has the spicy hot sauce they used in "Too Young."
- PB says, "Excuse me, Finn," just like in "Too Young."
- The events of "Frost & Fire" are referenced, when Jake mentions Finn "breaking up" with Flame Princess.
- Lemongrab 2 now has no legs, a bite mark on his head, and relies on a floating device to move. His injuries presumably come from when his brother ate him in "Another Five More Short Graybles," but he was eaten whole this time by Lemongrab after releasing Finn, Princess Bubblegum, and Lemonhope.
- The Lemon Children who were first seen in "All Your Fault" have been growing up, and can now talk.
- Finn's (previously broken) flute from "Prisoners of Love" returns.
- This episode continues the saga for the Lemongrab's food troubles. In "All Your Fault" the Lemon Kingdom had no food and the Earls used their seeds to make more children. In "Another Five More Short Graybles" they are arguing over raising a LemonPuppet, resulting in The Earl trying to eat his clone. In "Too Old" Earl succeeds and eats his Lemongrab clone.
- Lemongrab is shown to have five fingers in this episode, something very rare according to Cuber in the episode "Five More Short Graybles," in which he claims that "No one's had five fingers for twenty blablillion glaybels."
- When the Lemon Children are pulling at Finn's hat, he does not appear to have any hair.
- As Finn is talking to Jake at the end of the episode, a small part of Finn's phone disappears then reappears.
- When Lemongrab enters the bathroom to stop Lemonhope from playing his harp, he has to squeeze through the doorway to get in. However, when he leaves, he fits and is unobstructed.
- The synopsis listed on fios on demand and Itunes says, "Finn, Jake, and PB discover a talented mutant named Lemonsqueak at The Pageant of the Mutants. Now they must find a ways to free him from the lemongrabs." This description misspells Lemonhope's name as Lemonsqueak, and while Jake is also not present in the rescue of Lemonhope, the synopsis says that he is. In the episode, he stays at home. Also, it calls the gathering in Castle Lemongrab a pageant of mutants, when it is only PB, Finn, and all the Lemon People, including Lemongrab, at the gathering.
- Just as the floor show begins, Princess Bubblegum's place card says "PB HUMAH" instead of the original "PB."
- This is one of the many episodes in which Princess Bubblegum appears overly rational and laid-back, giving the impression that she does not enjoy having fun. In "Too Young," Princess Bubblegum is freed from responsibility and shows a more fun-loving side, and, in other episodes, she often behaves differently when excused from royal duties. The reason Finn seems to think that Princess Bubblegum is not as fun in this episode is probably not because of her overall personality, but instead because she is shown to constantly put her citizens, responsibilities, and morals before everything else. Finn's misunderstanding of this may be because of their age difference, once again supporting the idea that Bubblegum and Finn cannot be together due to age.
- Lemongrab's castle is relocated to a forest since in "All Your Fault," Lemonjon died with the castle falling.