The film opens with an evocative and haunting static shot of a cabin fireplace, where glowing yule logs crackle gently, accompanied by the soft strains of festive holiday music. However, this seemingly peaceful setting is underlined by its sinister past, including a tragic confrontation involving its original occupant, Isaac, an American slave owner. The narrative unfolds through a painful exchange with his slave, Rosa, who confronts him after discovering that Isaac failed to live up to his promise of selling her son William to a benevolent master. Instead, due to familial pressure, he has sold William to the cruel and sadistic Mr. Armfield. Overwhelmed by grief and betrayal, Rosa reacts violently, stabbing Isaac repeatedly with a knife before hiding the weapon in the very fireplace that will come to symbolize their dark history. Tragically, Rosa meets her end when she is lynched at a nearby tree.
Fast forwarding to the contemporary era, we meet the current owner of the cabin, whose intention is to prepare the place for incoming weekend renters. However, the atmosphere turns deadly when the deranged masked killer known as Pleatherface and his sinister mother invade the cabin; they brutally murder the owner and conceal her body, all the while plotting their next moves as the unsuspecting renters, Alex and Zoe, arrive to enjoy their getaway. As they settle in, a romantic moment unfolds by the fireplace when Alex proposes to Zoe. However, the tranquility is short-lived as they are interrupted by the local sheriff, Mark Costello, and his deputy, Jonathon Pawlowski, who alert them about a serial killer on the loose. Tension rises when the sheriff recognizes that the log burning in the fireplace was taken from the infamous hanging tree, a significant taboo. Before leaving, he extinguishes the log and warns the couple about the dangers that may lie ahead.
An unsettling argument ensues between Zoe and Alex about marriage, intertwined with Zoe's struggles with mental health issues. Their conversation is abruptly interrupted by the arrival of four additional renters—Ben, Beth, Holly, and Henry—who unknowingly show up at the same cabin for their investigation into local myths surrounding lynchings and alien encounters. As they navigate their way, Alex and Ben attempt to resolve the overlapping bookings, while Zoe's discomfort peaks when she discovers the owner's phone ringing ominously from beneath the couch. Distressed, she and Alex decide to pack and leave, but amidst the chaos, the fireplace reignites.
Unbeknownst to them, the cursed yule log, now a malicious entity, floats ominously toward Ben, who is in the shower, leading to his gruesome demise. Meanwhile, a fantastical twist occurs when Henry encounters a cryptic small figure emerging from the fireplace, beckoning him into a surreal burning realm. This figure reveals an elevator that traverses time and space through fireplaces, cunningly coaxing Henry into committing fratricide against his mother while he is in utero, thus tragically erasing his own existence.
Upon uncovering Ben's horrific fate, the remaining renters—now joined by Hunter—attempt to call for help, but the sentient log, echoing the voices of tormented past victims including Rosa, lashes out again. The situation escalates as Pleatherface and his mother ambush the group. In a shocking turn, the mother figure is killed by an alien that appears from a flying saucer, and it subsequently threatens Alex. In a desperate bid, Zoe retrieves the hidden knife from the fireplace and uses it to liberate herself from Pleatherface’s clutches, ultimately killing him in the process.
As they attempt to escape, Zoe is approached by the little man from the fireplace who offers her a dark choice: to erase her anxiety-ridden life by altering history to prevent her own birth. Defiantly, she rejects this notion of despair, affirming her will to live as Alex assists her in overcoming the little man's influence. Meanwhile, Holly flees into the dark woods, fleeing the horrors around her. Zoe and Alex manage to imprison the log and make their escape in a vehicle, only to find themselves drawn to the hanging tree where cultists gather for a dark ritual. In a shocking revelation, Zoe identifies her adversaries as the sheriff and deputy, leading to a reckless act of vengeance as they run them over.
As they drive away into the sunrise, a moment of tenderness unfolds when Zoe accepts Alex's heartfelt proposal. Yet, their happiness is abruptly shattered as the cursed log appears ominously outside their car window, signaling that the nightmare is far from over. The film then shifts unexpectedly to a contemporary setting, revealing Isaac working as a graphic designer in an Atlanta agency. Engaged in a discussion about leaving work early with Rosa, who is now his partner, their familial dynamic shifts in a moment of horror as previous identities resurface, culminating in a tragic end when the malevolent log crashes through their lives once again, leaving a trail of destruction in its wake.
