The episode "Treehouse of Horror XXIX" begins with a framing device where the Simpson family is preparing for Halloween. Homer is excited about the holiday, but Marge is concerned about the children's safety. They gather in the living room, and Homer suggests they tell scary stories, leading into the first segment of the episode.

The first story, titled "The Exor-Sis," features Lisa as a young girl who becomes possessed by a demon. The family notices Lisa's strange behavior, which includes speaking in tongues and levitating. Marge and Homer are initially confused and worried, but they decide to consult a priest. The priest arrives and attempts to perform an exorcism, but Lisa's possession proves to be more powerful than expected. The exorcism goes awry, leading to a chaotic scene where Lisa's demonic side fights back, causing havoc in the house. Eventually, Marge realizes that the only way to save Lisa is to embrace her true self, which leads to a heartfelt moment where Lisa is freed from the demon's grasp.

The second story, "The Biter," centers around Bart, who is bitten by a radioactive spider. After the bite, Bart gains superpowers similar to those of Spider-Man. He begins to use his powers for mischief, swinging around Springfield and causing trouble. However, as he revels in his new abilities, he soon discovers that he must face a villainous character, who is revealed to be Nelson, transformed into a monstrous version of himself. The confrontation between Bart and Nelson escalates, with Bart initially enjoying his powers but ultimately realizing the responsibility that comes with them. The battle culminates in a showdown where Bart must use his wits and newfound abilities to defeat Nelson, leading to a resolution where Bart learns a lesson about heroism.

The final story, "The Harvest," takes a darker turn as it depicts a dystopian future where the citizens of Springfield are turned into corn. The story begins with the townspeople celebrating a harvest festival, but it quickly becomes apparent that something sinister is happening. Homer, Marge, and the kids are captured by a group of corn farmers who plan to turn them into corn products. The family must work together to escape their fate, using their unique skills to outsmart the farmers. The tension builds as they navigate through the cornfields, facing various traps and challenges. In a climactic moment, they manage to outwit the farmers and escape, but not without a final twist that leaves the audience questioning the fate of Springfield.

After the three stories conclude, the episode returns to the Simpson family in their living room. They reflect on the stories they shared, with Homer expressing his enjoyment of the spooky tales. The family shares a moment of laughter, but the episode ends on a chilling note, hinting at the lingering effects of the supernatural events they experienced. The screen fades to black, concluding the Halloween special.

In the ending of "Treehouse of Horror XXIX," the three segments conclude with a mix of humor and horror. The first segment, "The Exor-Sis," ends with Lisa successfully exorcising the demon from Maggie, but the demon possesses Marge instead. The second segment, "The Bait," sees Homer and Marge trapped in a deadly game of cat and mouse with a monstrous version of Homer, who ultimately devours Marge. The final segment, "The Harvest," features a dystopian future where the family is forced to harvest their own organs, leading to a darkly comedic conclusion where they all end up in a gruesome fate.

Expanding on the ending in a chronological and narrative fashion:

The episode wraps up with the conclusion of its three segments, each filled with dark humor and horror elements.

In the first segment, "The Exor-Sis," the scene unfolds in the Simpson household, where Lisa, armed with a book on exorcism, confronts the demonic presence that has taken over baby Maggie. The atmosphere is tense, filled with flickering lights and ominous music. Lisa's determination shines through as she recites incantations, her face a mix of fear and resolve. Just as she seems to succeed, the demon is expelled from Maggie, only to find a new host in Marge. The scene shifts dramatically as Marge's demeanor changes, her voice deepening and her eyes glowing with an eerie light, leaving Lisa horrified and the audience laughing at the unexpected twist.

The second segment, "The Bait," begins with Homer and Marge enjoying a romantic evening, which quickly turns into a nightmare. They are lured into a deadly game by a monstrous version of Homer, who has been transformed into a grotesque creature. The tension escalates as Marge realizes the danger they are in. The scene is filled with suspense as Homer, now a predator, stalks Marge through the house. The emotional stakes rise as Marge tries to escape, her fear palpable. In a shocking turn, Homer catches Marge and, in a darkly comedic moment, devours her, leaving the audience in a mix of shock and laughter at the absurdity of the situation.

The final segment, "The Harvest," presents a dystopian future where the family is forced to harvest their own organs for survival. The scene is grim, with a bleak landscape and the family members looking gaunt and desperate. Each character faces their fate: Homer, Lisa, Bart, and Marge are all shown in various states of despair as they confront the reality of their situation. The humor remains dark as they bicker about who will sacrifice what organ, showcasing their dysfunctional family dynamic even in dire circumstances. The segment concludes with a macabre twist, as they all end up in a gruesome fate, highlighting the absurdity of their plight.

As the episode closes, the characters are left in their respective fates: Lisa is left to deal with the possessed Marge, Bart is likely to face the consequences of his actions, and Homer, having consumed Marge, is left alone in his monstrous form. The ending encapsulates the show's signature blend of humor and horror, leaving viewers with a mix of laughter and shock.

In "Treehouse of Horror XXIX," there is indeed a post-credit scene that adds a humorous twist to the episode. After the main credits roll, the scene opens with a dark, eerie atmosphere, reminiscent of classic horror films. The camera pans to a graveyard where we see the tombstones of various characters from the show, each marked with clever epitaphs that reflect their personalities or fates.

As the camera continues to move through the graveyard, it eventually focuses on a tombstone that reads "Homer Simpson." Suddenly, Homer's voice can be heard, expressing his confusion about being dead. He humorously questions the audience, wondering if he should have taken better care of his health or if he should have listened to Marge more often. This self-aware commentary is filled with his characteristic blend of humor and ignorance.

The scene concludes with a comedic twist as Homer's ghostly figure rises from the grave, only to be immediately pulled back down by a pair of hands, suggesting that he is not quite ready to leave the grave yet. This playful ending encapsulates the spirit of the "Treehouse of Horror" episodes, blending humor with a touch of the macabre, leaving viewers with a chuckle as they finish the episode.

The episode features three segments: 'The Simpsons' and 'The Shinning', 'The Evil House', and 'The Day the Earth Looked Stupid'.

In 'The Shinning', Homer is hired as the winter caretaker of the Overlook Hotel, where he becomes increasingly influenced by the hotel's supernatural forces, leading to a violent breakdown similar to Jack Torrance in The Shining.

In 'The Evil House', the Simpsons move into a haunted house that has a mind of its own, leading to a series of comedic and terrifying events as the house tries to eliminate them.

In 'The Day the Earth Looked Stupid', Bart is depicted as a young boy who is skeptical of the alien invasion, ultimately leading to a humorous twist where he becomes a key figure in the resistance against the aliens.

Lisa serves as the voice of reason throughout the segments, often trying to maintain a sense of normalcy and logic amidst the chaos, particularly in her interactions with the supernatural elements.

"Treehouse of Horror XXIX" from Season 30 of The Simpsons features several segments that may not be considered family-friendly for younger viewers or sensitive individuals. Here are some potentially objectionable or upsetting aspects:

1. Violence and Gore: The episode includes scenes with cartoonish violence, including characters being harmed or killed in exaggerated ways, which may be unsettling for children.

2. Dark Themes: The segments explore themes of horror and the macabre, including supernatural elements and existential dread, which might be frightening for younger audiences.

3. Parody of Horror Tropes: The episode parodies well-known horror films and tropes, which may include disturbing imagery or concepts that could be confusing or alarming for children.

4. Mature Humor: As with many episodes of The Simpsons, there are instances of humor that may not be appropriate for younger viewers, including innuendos or references that require a more mature understanding.

5. Scary Creatures: The presence of monsters and other frightening creatures may evoke fear or anxiety in sensitive viewers.

Overall, while The Simpsons often employs humor, the "Treehouse of Horror" episodes are known for their darker and more mature content, which may not be suitable for all audiences.