Adult Swim Yule Log

The film begins as a static shot of a cabin fireplace with burning yule logs, accompanied by holiday music. The cabin has a dark history across the ages, including with its original occupant: an American slave owner named Isaac, who ashamedly admits to his slave, Rosa, that he did not sell Rosa's son William to a kind slave owner as he promised her, but to the cruel and sadistic Mr. Armfield to fetch a better price. Devastated, Rosa screams that William was their son and stabs him repeatedly with a knife. She hides the knife in the fireplace, but is later lynched at a local hanging tree.
In the present, the owner of the cabin arrives to clean it before the weekend renters arrive. A masked killer "Pleatherface" and his mother break in and murder her. Hearing renters Alex and Zoe arrive, they hide inside the cabin. By the fireplace, Alex proposes to Zoe, but they are interrupted by the arrival of the local sheriff and his deputy, who inform them of a killer on the loose. The sheriff recognizes that the log burning in the fireplace was taken from the nearby hanging tree, a taboo. He extinguishes the log, advises them not to light it again, and departs.
Zoe and Alex argue about her apprehensions about marriage and her mental health struggles. They are interrupted by the arrival of four renters—Ben, Beth, Holly, and Henry—who accidentally also booked the cabin and plan to investigate lynchings and alien abductions linked to the cabin for their paranormal podcast. Zoe finds the cabin owner's phone ringing under the couch and, unnerved, she and Alex go pack to leave, while Ben showers, and the others go use the hot tub.
Unnoticed, the fireplace reignites on its own. The cursed burning yule log floats to the bathroom where Ben is showering and bludgeons him to death. Henry sees a small man talking to him from within the fireplace. The "Little Man in the Fire" beckons Henry to crawl into the fireplace and into a strange burning room. He enters the man's magic elevator, which can travel through time and space to any fireplace in existence. He shows Henry the fireplace of his childhood home where his mother is sleeping, pregnant with him. The man tricks Henry into gruesomely killing her, thereby erasing himself from existence.
Back in the cabin, the renters (now with their friend Hunter, instead of Henry) discover Ben's corpse. Beth calls the police and is killed by the sentient log. It cries out in Rosa's voice, as well as other anguished voices of past residents, and kills Hunter. The others hide, but are ambushed by Pleatherface and his mother, who are unaware of the log. Pleatherface ties up and sexually assaults Holly and Zoe. His mother assaults Alex in another room. An alien in a UFO arrives, killing Pleatherface's mother by sucking out her internal organs. It does the same to Alex, leaving him near death, and threatens Zoe before being decapitated by Pleatherface. The hidden knife drops out of the fireplace, and Zoe uses it to free herself and kill Pleatherface.
Before they can flee, Zoe is also entreated by the little man in the fireplace, who offers her the chance to free herself of her anxiety-ridden life by altering history so she would never be born. She resists him, stating that she wants to live, while he admonishes her for living in a privileged era. Alex helps her break free of his influence, while Holly flees into the forest. Alex and Zoe flee in the car. Their escape brings them by the hanging tree, where cultists have gathered. Zoe recognizes the sheriff and deputy among the cultists, and runs them over, driving on until sunrise. When they finally stop, Zoe lovingly accepts Alex's proposal, but they are surprised by the appearance of the log outside their window.
The film freezes, playing on a monitor at an Atlanta advertising agency. Isaac is a graphic designer working on a proposal for the new Armfield Cotton Mill Lofts, and his boss and partner Rosa lovingly suggests they leave work early to take their son William to a baseball game. As they talk, the office begins to burn and they shift into their previous identities. Isaac begs Rosa for forgiveness for what he did to their son. Rosa attacks him. As she does, the log, now ridden by the little man, smashes through Zoe and Alex's car window, seemingly killing both of them.