| Season 1, Episode 1|
|Airdate:||April 5, 2010|
|Story:|| Merriwether Williams|
"Trouble in Lumpy Space"
This is the first episode in Adventure Time. Here Princess Bubblegum accidentally creates horde of candy zombies whilst working on an experiment, and Finn and Princess Bubblegum must prevent the candy people from knowing about the impending attack.
Finn and Princess Bubblegum are in the Candy Graveyard doing a science experiment, and Jake and Lady Rainicorn are playing in the forest. Finn and the princess try to bring dead candy people back to life. Princess Bubblegum tests her decorpsinator serum on the dead Mr. Cream Puff. But instead of actually being brought back to life, he turns into a zombie who craves for sugar. He then spills the decorpsinator serum all over the graves of the dead candy people, and they rise as zombies as well. Princess Bubblegum tells Finn that the Candy Zombies will go to the Candy Kingdom as they crave for sugar and the candy people are made of sugar.
They summon all of the candy people to the candy foyer, where she announces that they are all going to have a slumber party. She tells Finn that if the candy people know about the zombies, they would explode when they get scared. During that time Starchy the grave digger searches for Princess Bubblegum to give her a bigger corpse shovel. He waits and finds a candy zombie craving for sugar. Starchy then freaks out and explodes. Back at the Candy Kingdom, Bubblegum makes Finn royal promise to not tell anyone about the candy zombies. Jake hears part of the discussion and begins asking what Bubblegum and Finn were up to. But because he royal promised to Bubblegum about what's going on, he keeps making up lies and tries playing Truth Or Dare, where Chocoberry dares Mr. Cupcake to take off his wrapper, and he asks Jake whether he prefers chocolate or fudge, and finally Jake dares Finn to tell what's going on.
Finn tries to dodge the question by trying to play Dodge Socks, but when he throws his sock, Jake smells Mr. Creampuff's scent because Finn kicked Mr. Creampuff when he attacked Princess Bubblegum. To make sure Jake doesn't find out about the zombies, he gets Jake to play Seven Minutes in Heaven with Lady Rainicorn. The zombies have arrived, and Finn tries to make the candy people to not know about the zombies by zoning out the noise with loud music and barricading all the exits and windows. Then Finn takes a look at Manfried the talking piñata, and he tells the candy people that the zombies are piñatas, and he blindfolds them so they do not see them. Soon they beat up all the zombies and start eating the candy that was stashed in them.
Jake and Lady Rainicorn come out of the closet and Finn tells them what happened, where time suddenly stops. The only people who are not frozen are Finn and Princess Bubblegum, who hasn't finished her equation yet. Suddenly, two Guardians of the Royal Promise arrive and abduct Finn and Bubblegum, where Finn has broken his royal promise and since Bubblegum cares for Finn, Finn's punishment is to solve math questions, which he is terrible at. At first Finn is given a really difficult math problem, but luckily one of the Guardians changes it to 2+2. Finn answers correctly and the Guardians reset time. Bubblegum realizes that 4 is the last figure she needs to perfect her decorpsinator serum, as she was too smart to see it. Finn and Bubblegum bring the zombies back to life, including Starchy, where everyone reunites with their former dead relatives. Finn promises to keep his promises from now on, and Starchy (despite not being a zombie anymore), craves for flesh and bites Finn's leg. Finn squeezes him, and he farts.