Season one, episode one: Slumber Party Panic

• Synopsis
  • Finn and Princess Bubblegum must protect the Candy Kingdom from a horde of zombies they accidentally created without the citizens of the Candy Kingdom finding out.
• Trivia
  • A zombie Finn can be seen in the episode.
  • Candy people exploding from fear is never mentioned again.
• Episode Connections
  • "From Bad to Worst" serves as a sequel for this episode.
  • The humanoid creatures on the title card bear a resemblance to the Fruit Witches in Dad's Dungeon.
• Production Notes
  • The episode was originally titled "The Royal Promise" and later "Slumber Party Slaughter."

Season one, episode two: Trouble in Lumpy Space

• Synopsis
  • Finn must travel to lumpy space to cure Jake of the lumps after he is bitten by Lumpy Space Princess(LSP) at Princess Bubblegum's Mallow Tea Ceremony.
• Trivia
  • This is the most heavily censored episode in Australia.
  • This episode has the first mention of Glob in the series.
• Errors
  • This is one of two episodes that did not originally include the waving snail the other being "Blood Under the Skin". The snail was added in later.

Season one, episode three: Prisoners of Love

• Synopsis
  • Finn and Jake must free themselves and seven princesses from the Ice King.
• Trivia
  • Ice King is seen with a tattoo of a penguin on his right buttock during his dialogue with the cosmic owl.
• Cultural References
  • The title references the 1931 popular song "Prisoner of Love."
• Production Notes
  • This episode was originally titled "Meet the Ice King."
  • There was originally a scene at the beginning that was cut that involved Finn and Jake suffering in the heat at the Tree Fort due to the Lava Man.

Season one, episode four: Tree Trunks

• Synopsis
  • Tree Trunks joins Finn and Jake on an adventure through the Evil Forest in search for the legendary Crystal Gem Apple.
• Trivia
  • This episode originally aired on Cartoon Network as the original version without the ending, but viewers everywhere complained that it was "too dark," so nowadays, the episode aired with the ending.
  • According to the book, "Adventure Time: The Original Title Cards (Vol 1)", the episode was originally titled "Tree Trunks: She's Steppin' Out!" but later changed because someone at Cartoon Network Studios did not like the idea.
• Episode Connections
  • The story of Tree Trunks' disappearance is continued in "Crystals Have Power."

Season one, episode five: The Enchiridion!

• Synopsis
  • To prove their skill as adventurers, Finn and Jake undertake a quest given by Princess Bubblegum to retrieve the Enchiridion, a legendary hero's handbook in which they must endure many trials to receive it.
• Production Notes
  • This was originally the first episode of the series, so season one would begin with Finn receiving the hero book (this episode) and end with him meeting his hero, Billy "His Hero".

Season one, episode six: The Jiggler

• Synopsis
  • Finn and Jake find a small creature and they adopt it due to its fun-loving ways and vibes while discovering the harm they do to it by taking it from its habitat.
• Trivia
  • The Tree Fort appears for the first time.
  • Finn calls grapes "purple whatevers."

Season one, episode seven: Ricardio the Heart Guy

• Synopsis
  • A smooth-talking heart-creature named Ricardio appears wooing over Princess Bubblegum, making Finn jealous while suspicious he may actually be a bad guy.
• Cultural References
  • Ricardio is a spanish abbreviation for pericardio, which means pericardium.
• Episode Connections
  • Ricardio returns in "Lady & Peebles"

Season one, episode eight: Business Time

• Synopsis
  • Jake thaws mysterious zombie-like business men from an iceberg who practice the ways of efficiency while forcing him and Finn into a sedentary lifestyle.
• Trivia
  • The Tree Fort is built differently than in other episodes.
  • It is revealed that satellites still orbit Earth and are still functional.
• Errors
  • In Business Time, when a shot of the treehouse is shown it has a completely different build to other episodes. This may not be an error and Finn and Jake may have merely rebuilt the treehouse from a previous event causing the treehouse damage so much so that they rebuilt the whole thing.
• Production Notes
  • Pendleton Ward later stated in an interview that this episode was when the show's writers decided the Land of Ooo was post-apocalyptic.

Season one, episode nine: My Two Favorite People

• Synopsis
  • Jake tries to improve relations between Finn and Lady Rainicorn so he can spend more time with both of them but may end up harming both friendships in the process.
• Trivia
  • Jake states that Lady Rainicorn can play viola.
  • Jake states that every day at 4:00 he practices viola with Lady Rainicorn, but in the Adventure Time series presentation it states that they practice every Thursday in Princess Bubblegum's Garage.

Season one, episode ten: Memories of Boom Boom Mountain

• Synopsis
  • Finn tries to reconfirm his desire for helping people out when confronted with one problem after another stemming from a violence-hating mountain.
• Trivia
  • Characters use the word "math" as a profane word, such as "Spin me the math around!" "You're creeping me the math out!" and "Math this!"
• Productions Notes
  • This episode was originally titled "Helping Hand."

Season one, episode eleven: Wizard

• Synopsis
  • Finn and Jake take up wizard lessons in order to gain free magic powers, but are ultimately tricked into stopping an asteroid.
• Cultural References
  • If you look closely on the title card, Jake has the word Dr. Seuss on his body.
• Production Notes
  • This episode was formally called "Finn the Wizard"

Season one, episode twelve: Evicted!

• Synopsis
  • Finn and Jake search for a new home after Marceline takes over theirs.
• Trivia
  • This is the first appearance of Marceline.
  • Marceline could not ride on a giant goldfish during the day because vampires die in the sunlight. The sunlight did affect her in "Henchman," so this likely means Marceline made the story up or it is an error

Season one, episode thirteen: City of Thieves

• Synopsis
  • Finn and Jake, in hopes of helping a little girl named Penny get back her stolen basket, enter into a city where everyone is a thief, and become slowly corrupted by their surroundings.
• Trivia
  • At some point, Penny's basket is stolen by a wizard. As a cyclops is about to steal the basket from the wizard, the wizard chants "Pancake" until he turns into a cat and escapes. This may be a reference to Natasha Allegri's cat, Pancake. Also, in the "Mystery Train" episode there is a definition for "Pancake" in the dictionary discovered by Finn. It says "when repeated three times this wizard incantation can change one into a cat."
• Cultural References
  • The concept that everyone in the city steals from each other may be a reference to the short fable The Black Sheep by Italo Calvino.

Season one, episode fourteen: The Witch's Garden

• Synopsis
  • After Jake steals one of the Witch's donuts, she steals Jake's powers and won't give them back unless he apologizes to her. During a series of events trying to find a way to get Jake's powers back, Finn's life is then held on the line, but will Jake's new laziness get the best of him?
• Trivia
  • The witch's spell "Magicusnomoreicus" gives the target a man-baby body and white briefs, as both Jake and the bagel are given them.
• Cultural References
  • The witch's appearance is a reference to the appearance of Kayako from the 2004 horror movie The Grudge.
• Episode Connections
  • The witch uses the magic word "Razzamafoo," which was previously used in the episode "Wizard." The spell appears to be used for teleportation.
• Production Notes
  • In a cut scene shown in one of the storyboards, the witch's video does end up on her newsletter, and a bunch of princesses and Lady Rainicorn watch it on a computer.

Season one, episode fifteen: What is Life?

• Synopsis
  • Finn creates a Never-Ending Pie-Throwing Robot Neptr to prank Jake, but it unexpectedly comes to life! Yet when he decides to use some of the Ice King's power to further develop it, this ultimately leads to a moral dilemma for the new living machine.
• Trivia
  • This episode is where Gunter first appears.
• Cultural References
  • The Title Card resembles one of Pixar's Up movie posters.
• Production Notes
  • This episode was originally called "Ice King and Son."[

Season one, episode sixteen: Ocean of Fear

• Synopsis
  • Finn discovers he's afraid of the ocean, so he enlists Jake's help to overcome his fear or risk failure.
• Episode Connections
  • Fear Feaster returns in the episode "King Worm," opening a chest and releasing Finn's fears, which include the ocean and other fears that were revealed throughout the show. It returns again in the season 5 finale "Billy's Bucket List," taunting Finn for his fear of the ocean once again, but it is cut by Finn's Grass Sword, and is presumed to be vanquished.
• Cultural References
  • The Fear Feaster and Three Wise Men are similar to the four humors: black bile, yellow bile, blood, and phlegm.
  • There is a real mental disorder called Amafufunyana, where patients believe evil spirits reside within them and they can hear voices from their stomachs.
• Production Notes
  • The episode was originally titled "Finn Underwater."
• Storyline Analysis
  • On the ocean floor are the remains of a city. The remains of forgotten cars, buildings, a destroyed tank, sunken aircraft carrier, and even people are further evidence of the Land of Ooo's post-apocalyptic setting.

Season one, episode seventeen: When Wedding Bells Thaw

• Synopsis
  • The Ice King is finally getting married, but consults Finn and Jake on whether or not to go through with getting hitched or keeping his life of abducting princesses.
• Episode Connections
  • The Ice King's Demonic Wishing Eye becomes an important plot point in "Reign of Gunthers."

Season one, episode eighteen: Dungeon

• Synopsis
  • Finn descends into a dungeon in hopes of finding adventure, but ultimately finding various obstacles that better fit being handled by Jake than himself alone.
• Cultural References
  • This episode contains tributes or parodies of traditional Dungeons & Dragons elements.
• Production Notes
  • This episode was originally titled "Dungeon Masters.
  • "Dad's Dungeon" originally had the working title "Dungeon."

Season one, episode nineteen: The Duke

• Synopsis
  • During a mishap accidentally caused by Finn, Princess Bubblegum becomes green and bald, and blames the Duke of Nuts for it, thus making Finn think he's a bad guy. Finn and Jake have no choice but to find the Duke of Nuts on Bubblegum's order.
• Trivia
  • This is the first episode where the snail appeared twice, in different places.
• Production Notes
  • This episode was originally titled "Duke of Nuts."
  • There was an alternative title card for this episode, in which the Duke was not smiling. This title card was later used on Netflix.

Season one, episode twenty: Freak City

• Synopsis
  • After a magic man turns Finn into a giant foot, he and Jake team up with a band of similar body part freaks to set things right and try to turn themselves back to normal.
• Cultural References
  • At the beginning of the episode, Finn says, "Hambone break!" Hambone is a form of dance which involves slapping one's body in place of rhythm instruments.
• Production Notes
  • This episode was originally titled "Good Buddies."

Season one, episode twenty-one: Donny

• Synopsis
  • When Finn and Jake see a bullying ogre named Donny, they help him turn his life around, unaware of the ecological consequences of their action.
• Trivia
  • This is the first episode where BMO has a speaking role.
  • Natasha Allegri's cat, Pancake, can be seen through the window of the house-girl with glasses.
  • When Mr. Bank is broken, it shows that the buildings are just shells they wear, rather than part of their bodies.
• Cultural References
  • The noises made by the terrified House People are also used in Daft Punk's song Revolution 909.
• Production Notes
  • This episode was originally titled "An Ogre Named Donny."
  • In the original storyboard for this episode, Finn was supposed to use an item called Steel-Toed Boot of Responsibility to make Donny return to the House People's village.

Season one, episode twenty-two: Henchman

• Synopsis
  • Finn fakes the place of Marceline's henchman, and he finds out how hard it is to obey her strange ways.
• Trivia
  • The old man henchman was actually just Marceline's old diving buddy.
• Production Notes
  • This episode was originally titled "Marceline's Slave Story," then "Marceline's Henchman."
  • The original beginning of this episode was supposed to have Marceline rescuing Finn and Jake from a sudden fall off a cliff and then Finn repaying her by being her henchman.

Season one, episode twenty-three: Rainy Day Daydream

• Synopsis
  • When a knife storm forces Finn and Jake to stay inside, they discover the out-of-control power of Jake's imagination.
• Trivia
  • This is Pendleton Ward's favorite episode from the first season.
• Cultural References
  • The riddle master saying that the penalty for answering a riddle incorrectly is death is a reference to the Sphinx, a creature that kills anyone who cannot answer its riddles correctly.
• Episode Connections
  • BMO will say, "Who wants to play video games?" again in "Jake the Dad."
• Production Notes
  • This is the first time an episode was storyboarded by only one person.

Season one, episode twenty-four: What Have You Done?

• Synopsis
  • Finn and Jake capture Ice King under order of Princess Bubblegum without even knowing what he has done wrong.
• Cultural References
  • The fumigation suit the Princess is wearing is modeled after a plague doctor costume, which was worn by doctors during the Black Death, and has since become a popular Venetian Carnival costume. Although, being Princess Bubblegum, the typical black was changed to pink.
• Production Notes
  • This episode was previously titled "Ice King Has a Point."
• Storyline Analysis
  • Princess Bubblegum's medicine book depicts Ice King's wails of pain directed to possible candy people, implying that Freezer Burn Flu has happened before.
  • The Ice King claimed he got his crown with the power he stole. This is later proven wrong in "Holly Jolly Secrets Part II," when Simon Petrikov states that he purchased the crown. The reason for Ice King thinking otherwise is explained even further in "I Remember You," where it is revealed that he has almost no memory of his past life, and "Evergreen", where the story behind the crown's creation is revealed, as the crown was created with magical jewels stolen from Magwood by the Ice Elemental Urgence Evergreen.

Season one, episode twenty-five: His Hero

• Synopsis
  • Finn and Jake discover Billy, the greatest hero who ever lived, and try to help other people without using violence in their methods.
• Trivia
  • Billy is enemies with the Fire Count and friends with Cotton Candy Princess, whereas Finn is enemies with the Ice King and friends with Princess Bubblegum. However, Billy has slain the Fire Count, but Finn has not slain the Ice King.
  • This is the first episode (and the only season 1 episode) to be banned from airing on Cartoon Network Australia and Philippines.
• Cultural References
  • The title card is a homage to fantasy illustrator Frank Frazetta's Death Dealer
• Episode Connections
  • Billy was the only person known to have harmed the Lich until Finn does the same in "Mortal Folly."
  • In the flashback of Billy fighting with the Lich, we can see that this one have both horns, but in the episode "Finn the Human," in another flashback prior to being defeated by Billy, he(the lich) already lost one.
  • The way Cotton Candy Princess gives Billy some of her hair is similar to how Princess Bubblegum gave Finn some of her hair in "To Cut a Woman's Hair;" though, Finn decided to keep the hair while Billy ate it.
  • Billy slaying the Evil Ocean is similar to Finn conquering his fear of the ocean in "Ocean of Fear."
  • When Billy defeated the giant bear, it is similar to when Finn rehabilitated the Bear in "In Your Footsteps," which ironically leads to Billy's death at the hands of the Lich with the Bear's help in "The Lich."
  • When Billy is shown beating the Lich, he is wearing his gauntlet, proving it was the only known weapon to harm the Lich as stated in "Mortal Folly."
• Production Notes
  • This episode was originally titled "Finn Meets His Hero."
  • Billy said that the Mini Queen was probably dead after Finn and Jake rescued her. In the original storyboard she was taken by goblins after she left Finn and Jake.

Season one, episode twenty-six: Gut Grinder

• Synopsis
  • When the gold owned by several beings were devoured by a creature called the "Gut Grinder," Finn and Jake set out and discover who's the culprit, while trying to sustain Jake's thoughts that he is the actual Gut Grinder.
• Trivia
  • This is the final episode that Derek Drymon was executive producer for.
• Cultural References
  • One of the signs in the Soft Village says "Fluffer Nutter." A Fluffernutter is a sandwich that contains peanut butter and marshmallow creme.
• Errors
  • In this episode, Finn states that Jake has been his best friend for as long as he can remember, but in "Memories of Boom Boom Mountain," Finn talks about himself all alone in the woods as a baby.