An elderly couple is found in their living room, suffering severe bleeding from their nose, ears, and eyes. As they scream in horror, an unseen figure enters the room, leaving a sense of dread hanging in the air.
Fast forward two months, we meet friends Eugene and William as they discuss their future aspirations at a pub in their small hometown of Six Mile Hill. This quaint town is known for its historical connection to Bram Stoker, who once stayed there and drew inspiration from the local legend of Abhartach, a figure believed to be buried under a cairn in a nearby field owned by William's family. Although the town hinges on its reputation as a tourist destination, Eugene, William, and their companion SP often entertain themselves by scaring tourists who come seeking the mysterious cairn.
Eugene works as a construction laborer under his father, Francie. Francie pressures Eugene to assist him with a profitable venture that involves excavating land for a new bypass, which would sadly erase a significant portion of the land belonging to William's family. During a casual walk through the field, William shares his plight with Eugene, revealing that he intends to emigrate to Australia due to the impending construction. Eugene then confesses that it is his father's company behind the destruction, leading to a heated argument. Ignoring his father George's warnings, William is suddenly charged at by a wild boar, fatally injuring him against the cairn while blood seeps into the soil after he cuts himself on the stones.
After William's funeral, Eugene, Francie, and SP are thrown out of The Stoker, the local pub, as their behavior threatens the town's tourist revenue. However, construction proceeds as planned, and Eugene takes matters into his own hands by obliterating the cairn. Later that evening, in a drunken state, Eugene and his friend Claire share tales of their losses. Meanwhile, at the construction site, Charlie, another worker on night duty, is violently assaulted by a mysterious presence.
The next day, when Eugene, Francie, Claire, SP, and Gabriel return to work, they discover the cairn has been mysteriously restored, and Charlie is missing. As night draws in, Charlie reappears, confused and bleeding, only to lunge at Eugene during a frantic drive to the hospital, which leads to a crash. After the accident, darkness engulfs them, and Gabriel suddenly disappears.
Searching for Gabriel, Francie and SP venture deeper into the site while Claire and Eugene look for torches in the portacabin. It is here that Eugene is attacked by a deranged Charlie, only to be saved when Claire impales Charlie through the heart with a metal pole. Tragically, they find Gabriel dead, his throat violently slashed. Yet, Charlie's ferocity seems unmatched, as he rises again, forcing Claire to bury him under debris, which ultimately ends his reign of terror. As Gabriel's blood seeps into the ground under the cairn, Abhartach is resurrected.
The group takes refuge in George's home where his wife, Pauline, remains in a catatonic state after losing William. A distraught George points a gun at the group, revealing that William is now a feral vampire kept in a cell, having been fed sheep by George himself. He explains that it is the cairn stones, not a bite, that turns someone into a vampire. Desperate to halt the construction, George admits to deliberately infecting Charlie. The group decides to assist George in eliminating the vampire threat.
They devise a plan to confront William, leading Eugene to release him from captivity. In a tense moment, George prepares to decapitate Eugene with an axe, but Pauline intervenes, shooting George in the shoulder while attempting to embrace William. In a devastating turn, William kills Pauline and then George after draining her blood. The group manages to ambush William, locking him away, though they suffer another loss as SP is killed during the chaos.
Meanwhile, Abhartach is terrorizing the town, able to drain the blood of unsuspecting victims even from a distance. With the townspeople in peril, Eugene, Claire, and Francie bury William under soil and cairn stones before heading back to their dump truck, discovering most of the townsfolk have been left bloodless. As Claire stays to care for her mother and stepfather, Eugene and Francie realize Abhartach's lair is at Eugene's late mother's house due to the presence of deceased animals nearby.
Upon arriving, they catch Abhartach in the act of draining the town's blood. In a dramatic confrontation, Francie knocks Eugene unconscious to face Abhartach alone. Though he initially beheads the creature with an axe, Abhartach revives and injures Francie. Desperate, Eugene and Francie escape into a barn as dawn approaches, but sunlight proves ineffective against the vampire. In a last-ditch effort, Eugene uses his father's severed leg to stun Abhartach, ultimately burying him under the rubble. As the townspeople awaken from their nightmarish ordeal, Francie praises Eugene for his bravery.
Three months later, Eugene and Claire share a bittersweet drink before she departs for Australia for a year, while his house is finally transformed. However, the threat of Abhartach lingers, as he remains entombed in the barn beneath a steadfast cairn crafted from stone, brick, and slate, suggesting that their ordeal may not be entirely over.
