"All Your Fault" is the ninth episode in the fifth season of Adventure Time. It is the one hundred and thirteenth episode overall.
A mission to help the Earls of Lemongrab lead Finn and Jake to discover grotesque new developments in the Lemon Kingdom.
Princess Bubblegum is doing research when she gets a message from the Earl of Lemongrab and Lemongrab 2 saying that they're out of candy and they demand her, blaming her despite the fact she left them with enough to last a lifetime. Bubblegum sends Finn and Jake to the Lemon Kingdom with Candy seeds so the Lemongrabs can grow more candy.
As Finn and Jake arrive at the Lemon Kingdom, they are confronted by Lemon people, distorted creatures who resemble the Lemongrabs. The Lemon people, starving from lack of food, attempt to eat Finn and Jake, forcing them inside the Castle Lemongrab. Here they meet Lemonjohn, a giant Lemon person who informs them that the Lemongrabs are in the dungeon and show 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 accidently left the formula of Candy life at Castle Lemongrab and they used all their candy to create their own candy people, locking themselves in the dungeon to prevent their citizens from getting any candy so they could create more citizens. They use the candy seeds to make another lemon person and Finn suggests they see Princess Bubblegum. They gather all the lemon people together and the Lemongrabs announce they intend to steal all the candy from the Candy Kingdom and use it to make an army that will steal all the candy from the world so they can eat it. They send Lemonjohn to carry out the task of destroying the kingdom.
Finn and Jake remember seeing the giant Lemonjohn's organs spread around Castle Lemonjohn and attempt to stop him by smashing his exposed heart. However, doing so causes his heart to start beating and gave him emotions. He realizes what he's doing is wrong and decides to sacrifice himself for the Lemon Kingdom, exploding himself into a mountain of lemon candy for them to eat. Later, Princess Bubblegum erases the Candy life formula from the Lemongrabs' mind and remarks that there's nothing wrong their hearts, but they're alway like this.
- This is the first Lemongrab episode without him saying his catchphrase acceptable or unacceptable.
- It was revealed that Princess Bubblegum created the Candy Kingdom through the process of Candy life.
- The way that Lemongrab and Lemongrab 2 speak (completing the sentence of each other) and walk (on a simetric way), is a well know trace of twins to act, such as Si and Am from Disney's Lady and the Tramp and I and Am, bounty hunters from the series Samurai Jack.