Evil Dead Burn

At the Price family vacation house, Joseph Price discovers his late grandfather Benjamin's research, revealing that the Circle of the Wise Men used the Necronomicon to unleash flesh-possessing demons known as Deadites before discovering the Kandarian Dagger, which can banish them back to Hell. Joseph inadvertently removes the spells concealing the dagger from the Deadites.

Some time later, Joseph's brother, Will, argues with his wife, Alice, before drunkenly driving away. On a rural road, the Deadite-possessed Jessica steps in front of his car, causing him to crash. As Will burns to death, the decapitated Jessica recites a passage from the Necronomicon, transforming him into a Deadite.

At Will's cremation, Alice is reunited with Joseph, his girlfriend Thya, his parents Susan and Edgar, and his dementia-afflicted grandmother, Polly. Alice remains distant following Will's death. Afterwards, Edgar privately visits Will's coffin, where Deadite Will breaks free, kills the crematorium attendant, and burns Edgar's arm. The family returns to the house, where Edgar gradually succumbs to possession. At dinner, he blames Alice for Will's death before fatally stabbing the family dog Max. Joseph and Thya drive him toward a hospital, but Edgar fully transforms into a Deadite and crashes the car. Joseph abandons Thya and flees as Edgar kills her.

Alice is attacked by a resurrected Max before reuniting with Joseph at the house. Deadite Thya arrives and attacks the family before being trapped in the cellar. Outside, Edgar repeatedly shoots himself in the head without dying. While Alice, Joseph, and Susan struggle to understand what is happening, Thya tricks Polly into releasing her and infects her before Joseph bludgeons Thya to death. The ordeal triggers Alice's memories of Will's physical abuse. When questioned by Alice, Joseph reveals Benjamin's research about the Deadites. Polly later transforms into a Deadite and promises Susan that the family can be reunited, including Will, convincing her to let Edgar into the house. Edgar and Susan kiss, infecting her, before the couple demand that Joseph surrender the dagger in exchange for sparing the family. When Joseph refuses, Edgar mortally wounds him and attacks Susan. Alice hides as memories of Will's abuse continue to haunt her.

Exploring upstairs, Alice is ambushed by Polly, who convinces Susan to help kill her, but Alice subdues Polly and ties her to her stairlift, which drags her downstairs. Alice and Susan barricade themselves in a bathroom, but Alice restrains Susan for helping Polly. Susan blames Alice for destroying the family, while Alice accuses Susan of ignoring Will's abuse to preserve the illusion of a perfect family. Susan finally transforms into a Deadite and attacks Alice, who escapes into the attic. Deadite Joseph pursues her, but Alice finds the dagger and kills him with it, ending his possession. Alice escapes onto the roof, pursued by Susan and Edgar, before climbing back into the house through the chimney. She decapitates Susan with a rotary saw, seriously wounds Edgar, sets the house ablaze, and kills Max with the dagger. Collapsing outside, she hears Will's voice and sees his charred Deadite form standing before the burning house.

Alice flees to a nearby construction site, where Will cripples her leg and traps her in a pit filling with boiling tar. She fights him with a jackhammer before finally stabbing him with the dagger. Alice then sees a vision of Will restored to human form, telling her he loves her. She tearfully replies, "That's not enough", before crushing his Deadite head with her hands. Wounded, Alice crawls onto the road, where police and paramedics arrive. When asked who inflicted her injuries, she replies, "My ex-husband".

In post-credit scenes, Polly is revealed to have escaped after severing her own leg and attacks a passing motorist. Meanwhile, Deadite Ellie Bixler is resurrected at the crematorium housing her unclaimed ashes and kills the manager's daughter.