"All Your Fault" is the ninth episode in the fifth season of Adventure Time. It's the one hundred and thirteenth episode overall.
A mission to help the Earls of Lemongrab leads Finn and Jake to discover grotesque new developments in the Lemon Earldom.
Princess Bubblegum is doing research when she gets a message from the Earl of Lemongrab and Lemongrab 2 saying that they are out of candy and that they demand she send them all of hers, blaming her despite the fact she left them with enough to last a lifetime. Bubblegum sends Finn and Jake to the Lemon Earldom with Candy seeds so the Lemongrabs can grow more candy.
As Finn and Jake arrive at the Lemon Earldom, they are confronted by Lemon people, distorted creatures who resemble the Lemongrabs. The Lemon people, starving from a lack of food, attempt to eat Finn and Jake and force them inside the Castle Lemongrab. Here they meet Lemonjon, a giant Lemon person who informs them that the Lemongrabs are in the dungeon for three weeks and shows them the way to it.
After traveling through the innards of the castle, they find the dungeon and discover the malnourished Lemongrabs. They find out that Princess Bubblegum accidentally left the formula of Candy life at Castle Lemongrab and they have used all their candy to create their own candy people. The reason they've locked themselves in the dungeon is to prevent their citizens from getting any candy so they can create more Lemon people. Finn and Jake give them the candy seeds, but instead of planting them they use the candy seeds to make another Lemon person. Finn suggests they see Princess Bubblegum. The Lemongrabs gather all the lemon people together and announce that they intend to steal all the candy from the Candy Kingdom, then use it to make an army that will steal all the candy in the world. They send Lemonjon to carry out the task of destroying the kingdom.
As Lemonjon heads to the Candy Kingdom, Finn remembers seeing the giant's organs spread throughout the Lemon castle. Jake says that they will never find his heart again, before Finn sees that there is a vent on the castle's exterior leaking the same juice they had previously seen pouring from Lemonjon's heart. Going inside the vent, they then attempt to stop him by smashing his exposed heart. However, doing so causes his heart to start beating and gives him emotions. He realizes that what he is doing is wrong and is confused at what he is about to do, but then decides to sacrifice himself for the Lemon Earldom, dissolving himself into a mountain of lemon candy for them to eat. Later, Princess Bubblegum erases the Candy life formula from the Lemongrabs' minds (Finn remarking that he also took the Candy life formula from the Lemon castle), causing Jake to ask if he could just do the same to the Lemongrabs' hearts as he did to Lemonjon's so they can be more selfless and less selfish. Princess Bubblegum responds that there is nothing wrong their hearts, but that they are just "like this."
- The Lemongrabs refer Princess Bubblegum as their mother, calling her "Mother Princess."
- The lemon castle looks different than it did in "You Made Me" and the trees outside have a different color. In "You Made Me" they were pink, but now they are green.
- After Princess Bubblegum read the Lemongrabs' letter, she exclaims "bullgunk" which is a censored version of the vulgar word "bullsh*t."
- The way that Lemongrab and Lemongrab 2 speak (completing the sentence of each other) and walk (in a symmetrical way), is a well known trait of twins, such as Si and Am from Disney's Lady and the Tramp and I and Am, bounty hunters from the series Samurai Jack.
- The way that Lemonjon's heart starts to pump and enlarge is similar to how the Grinch's heart in the How the Grinch Stole Christmas does.
- The bow Jake wears at the beginning of the episode resembles the one Isabella wears in Phineas and Ferb.
- Princess Bubblegum, Finn, and Jake salute in a similar manner to that of the United States military.
- The Lemon Head who screams as his skin rips off is a reference to the 1982 snow and alien terror film "The Thing". When Peter Maloney's character, "George Bennings", becomes possessed by the Thing and begins to turn into the titular monster, he screams and turns his head in a very similar way.
- Lemonjon could be a reference to John Lennon; in one episode of the Simpsons called "The Bart of War" Bart and Milhouse go to Flander's house and find sodas based on the names of The Beatles and drink one called "John Lemon."
- The title card is a reference to a scene in the Simpsons episode "Bart Vs Thanksgiving".
- The TV-PG rating originally faded in while Lemonjon was having a conversation with Finn and Jake. However, for later airings, TV-PG was re-located back to the Adventure Time Opening Sequence.
- When the Lemongrabs are giving a speech to the Lemon people, Lemongrab 2 seems to be missing his ribcage linings on his chest.
- Jake leaves the bow he was wearing and the glass he was holding on the tablecloth, but when Cinnamon Bun is saying bye to him they are gone.
- When Princess Bubblegum is going to package the last candy seed, they are seen in a different order than they were when Finn and Jake came in. Also, when Finn and Jake show the Lemongrabs the seeds they are in the same order Princess Bubblegum packaged them, but when Lemongrab goes to grab them they are in a different order.
- When Lemonjon carries the castle toward the Candy Kingdom he passes through the Candy Forest, despite the fact that the Candy Forest is located near the Candy Kingdom, which is still far away.
- When the Lemongrabs are giving their speech Lemonjon seems to be in a different room than the one Finn and Jake first found him.
- When Lemonjon stands up the castle looks different than it did when Finn and Jake were arriving.
- Before Lemonjon stands up, it can be seen that the two stumps outside the castle where the lemon guards were sitting on are gone.
- The road to the lemon castle looks different than it did in "You Made Me."
- Among the many words written on Lemongrab's brain are misspelled ones such as "posessed" and "asperagus."