The 8th Night (2021)

2,500 years ago, a monster crossed from hell into the human realm to create human suffering. Buddha ripped both its Red Eye and the Black Eye and sealed them in separate Śarīra caskets, which were buried in the Far East and Far West. In the present day, Professor Kim Joon-cheol discovers one of the caskets in the desert, but his findings are dismissed as fraudulent. Fourteen years later, Professor Kim, now a bitter individual, is determined to prove the truth of his discovery by reuniting the Black Eye and Red Eye. He opens the casket and pours six vials of blood into it from himself and members of his meditation group. The Red Eye emerges from the casket, presumably possessing him, beginning a chain of deaths among the group's members.

In Gwangju, Bhante Ha-jung, protector of the Black Eye casket, realizes the Red Eye has reawakened and tells the young Cheong-seok that it must be stopped before it reunites with the Black Eye. Ha-jung dies soon afterward, leaving Cheong-seok to find his former disciple, Bhante Seon Hwa. Meanwhile, in Chilgok, the Red Eye moves between human hosts, leaving victims whose bodies are shriveled and decomposed. Detectives Kim Ho-Tae and Dong-jin investigate the strange murders, eventually discovering their connection to Kim Joon-cheol's meditation group.

Cheong-seok finds Seon Hwa, who had abandoned the monastery after the deaths of his wife and daughter and refused to become Ha-jung's successor. The two set out to find the seventh "pillar," believed to be a Virgin Shaman who can prevent the Eyes from meeting. Their search leads them to a young woman named Ae-ran and a mysterious shaman. Seon Hwa believes Ae-ran is the seventh pillar and attempts to kill her, while Cheong-seok takes her away to protect her. Meanwhile, Detective Kim and Dong-jin uncover the connection between the meditation group, the victims, and the Virgin Shaman.

It is revealed that the woman Seon Hwa tried to kill is the real Virgin Shaman, while Ae-ran is the ghost of an abused girl whom Professor Kim once rescued. Kim had groomed Ae-ran to become a sacrifice and manipulated members of his meditation group into giving blood through supposedly free health tests. Ae-ran subsequently manipulated the Virgin Shaman and Dong-jin to further Kim's plan. The Red Eye ultimately possesses Dong-jin and heads to Gwangju, where Cheong-seok and Seon Hwa attempt to stop it.

Seon Hwa and Cheong-seok devise a plan to trap the Red Eye inside Dong-jin and kill him, but the Red Eye reveals that Cheong-seok himself is actually the seventh pillar. Because Seon Hwa never became Ha-jung's successor, the role passed to Cheong-seok, making him the only person capable of opening the casket containing the Black Eye. The Red Eye possesses Cheong-seok and pursues him, while Seon Hwa and Detective Kim try to intervene. The Red Eye uses Cheong-seok's appearance to torment Seon Hwa over his family's deaths, but Seon Hwa resists and manages to transfer the Red Eye into himself using a blood-drawn talisman.

Possessed by the Red Eye, Seon Hwa asks Cheong-seok to kill him before the Eye can reunite with the Black Eye. Cheong-seok kills Seon Hwa, preventing the two Eyes from being reunited. Later, Cheong-seok returns the Śarīra casket to the place where it was originally discovered. Ae-ran's spirit appears before him, and when Cheong-seok offers his hand, the chains binding her spirit fall away, finally freeing her.