Picking up directly after the events of the previous films, Shin Si-ah’s character — now immensely powerful yet painfully tormented — faces the emotional and physical fallout of her past battles. Her mysterious origins intertwine with an ancient prophecy foretelling an impending darkness that only she can either prevent… or unleash. Central to the narrative is her struggle to understand and control her evolving supernatural abilities while confronting both inner demons and mounting threats around her.

As the story deepens, a chilling revelation emerges: a malevolent alien entity has been manipulating events from the shadows, seeking to exploit Shin Si-ah’s powers for its own sinister purpose.This being — a remnant of a forgotten cosmic war — introduces a new dimension of sci-fi horror. With the ability to distort reality and conjure nightmarish illusions, it becomes a terrifying adversary unlike anything seen before in the series.

Forced into an uneasy alliance, Shin Si-ah joins a small group of renegade scientists and mystics who also understand the cosmic danger. Their journey takes them through increasingly perilous and surreal landscapes — from desolate, haunted wastelands to sleek, high-tech laboratories filled with secrets.

The film’s climax delivers a breathtaking fusion of witchcraft and advanced technology as Shin Si-ah confronts the alien entity and its monstrous followers in a visually stunning battle.

The finale unveils a shocking twist: she sacrifices her own powers to imprison the entity, losing her memories and identity in the process. Her ultimate fate remains uncertain, leaving the door open for future conflicts.