Forever Evil

Three couples gather for one last party at a lakeside cabin before they move out. Holly slips away to shower and a scream rings out, revealing she has been murdered with her entrails ripped open and her unborn baby missing. Panic spreads as the festive mood shatters into horror.

Marc Denning becomes the sole survivor while his lover, his brother, and three friends are killed around him. A woman is found hanged in the living room, another is dragged out the window by a tree branch, and a red-eyed attacker stalks the carnage. Denning stumbles through the chaos, questioning what kind of evil could have done this.

The zombie-like creature continues to menace the survivors, stalking Denning and his companions. He fights back with a fire poker, rips out the creature's eye in the struggle, and barely escapes its reach. The threat remains, hinting at a supernatural force behind the massacre.

Denning wakes in a hospital bed with a broken leg and three broken ribs, a brutal reminder of the cabin attack. Police begin their investigation into the murders, collecting evidence and questioning the lone survivor. Denning resolves to search for answers about what really happened.

A red-caped tarot reader named Brother Magnus reads the cards for an unidentified Southern-accented woman. The woman is attacked, and a shadowy red-eyed cowled figure appears in Magnus's doorway. He fires, but bullets bounce off the entity as it zaps him, hinting at something supernatural.

Denning is investigating at the library when Reggie, a survivor of a previous massacre, introduces herself. They travel with Lieutenant Leo Ball to the house of a psychic named Ben, who is identical to Brother Magnus. Ben leaves a box of old books for Leo to examine, including The Necronomicon.

Denning learns that Ben is identical to Brother Magnus, and a letter Ben left reads 'He is coming back,' which Denning interprets as a reference to Yog-Kothag. The letter deepens the sense that an ancient god may be behind the killings.

Reggie and Denning discuss cosmic connections while a sinister dog appears again. Leo teaches Denning to use a gun, and Denning studies a magazine article about quasars. He realizes the murders form a pentagram with the Nash real estate agency at the center, linking the killings to Yog-Kothag.

The duo attends a movie called The Jet Benny Show. Leo receives a document via mail and mails it to Denning, unwittingly triggering danger. A boiling cloud and a ray strike a car, and Leo is attacked and dies; Denning wakes from a dream, realizing Leo is in trouble.

Denning maintains contact with a professor via telephone about pulsars and the coming pulse dates. His secretary, Lisa, plots the killings on a map and reveals that the murders form a pentagram centered on Nash Real Estate.

The zombie returns and attacks Denning and Reggie; they fight it with a fire poker and later a car, but the creature keeps returning. Reggie confesses her love for Denning, and the zombie stabs Denning with a mystical dagger; Denning retrieves the dagger and stabs the zombie.

Nash seems to witness Holly’s reappearance, ripping open her womb to take out a baby with glowing red eyes. The sight feels demonic and seems to be a dream, but it foreshadows Nash’s dark powers.

Reggie confronts Nash and discovers his superhuman powers and bulletproof demeanor. Nash shows her his birth certificate, proving he was born over a hundred years ago, revealing that the apparent cult is actually Nash and his zombie.

The zombie is killed, but Nash reveals that Denning has been transformed into a new zombie, with Yog-Kothag speaking through him. Denning then asserts control and stabs Nash with the mystical dagger.

The ending cuts to Yog-Kothag's voice proclaiming the warning, and a final text repeats that 'Somewhere, a man named Nash is screaming' as Nash's cries fade into the void.