The film begins with Dimas, a journalist, working late into the night on an article about an illegal nickel mining operation in Borneo, wherein several workers have perished under enigmatic circumstances. After finalizing his piece, he promptly submits it to his editor, who summons him to his office. There, the editor harshly criticizes Dimas’s work, expressing concern that the focus on the workers' deaths might tarnish the newspaper's reputation given its current financial struggles. Consequently, he orders Dimas to rewrite his article. Following this tense interaction, the editor has a heated argument with his wife over the phone, further deepening his agitation. As he turns away from the window, a haunting figure becomes visible in his reflection. Tragically, he is subsequently murdered by an unseen assailant, who stabs him repeatedly with a pen. The horror escalates as a colleague discovers Dimas standing in the office, appalled, as his editor's lifeless body dangles from the ceiling fan.
The narrative then shifts to Labuhan Angsana prison, a facility rife with challenges, where inmates endure oppression from the prison guards and face hostility from other prisoners. Here, we meet the primary characters: Anggoro, who is continually subjected to extended sentences for defending fellow inmates; Six, who, despite lacking religious belief, claims to see spirits; Wildan, a devout Muslim; Pendi, a former professor; and their companion Irfan.
Soon after, Dimas is introduced to the prison, having been sentenced for the murder of his boss. The following day, while alone in the showers, one of the most dangerous inmates encounters a disturbing apparition—his own likeness, but with eyes obscured by black dots. This figure brutally murders him, leaving his body disfigured. Shortly thereafter, another inmate meets a grim fate after discovering his wife's infidelity.
During these events, Six informs the group that he can now perceive auras, noting a red aura around the second victim just before his death. Wildan explains that a red aura signifies an angry and negative disposition, leading the group to deduce that a malevolent ghost is present in the prison, eliminating inmates with the most negative energies. Determined to protect themselves, the inmates decide to maintain positive auras—praying and engaging in artistic endeavors like dance. However, word of this strategy spreads and, despite their efforts, the prison's dance instructor is murdered by the ghost after admonishing the students for distraction, illustrating that even positive auras might not protect them forever.
In light of these tragedies, Anggoro rallies the prisoners to confront the ghost. They theorize that Dimas has unwittingly transported this vengeful spirit from Borneo, where the miners suffered similarly violent and unnatural ends. It appears that the ghost uses these killings to rejuvenate itself and must find a target close to Dimas in order to strike.
One of the guards reveals that among the privileged politicians housed in the prison's luxury section is linked to the illegal mining scheme that Dimas was investigating. The inmates scheme to infiltrate this area and manipulate the politician’s aura into negativity. Cleverly, Pendi calls the politician, stirring memories of his early, more principled days in politics, which darkens his aura. With the ground set for revenge, the ghost attacks and kills the corrupt politician, signaling a satisfaction in its quest, as Six can now sense Dimas’s aura too, implying that the ghost has departed.
Fast forward six months, Dimas bids farewell to his fellow inmates as new surveillance footage emerges, proving his innocence regarding the murder of his boss, as he was nowhere near the scene. With this newfound freedom, he announces his intention to return to Borneo, aiming to escort the ghost back to its rightful place.
