Asia did not enter The Virgil by accident. Having served a ten-year prison sentence for shooting her abusive father, she used a false identity to secure employment after tracking her missing younger sister Maria to the building. Once inside, Asia discovers the horrifying secret behind the residents' power: the tenants have achieved biological immortality through an ancient blood pact with a demonic entity residing on the 9th floor.
Because the cultists rapidly regenerate from standard injuries, Asia is forced to adapt her tactics, using decapitations, dismemberment, and fire to destroy them permanently. Ascending the floors, Asia discovers Maria was not imprisoned in a dungeon but groomed into becoming an acolyte by Lily Woodhouse through promises of security.
In the penthouse climax, Asia confronts Lily and the demonic porcine entity. Asia manages to break through Maria's indoctrination, and the sisters unite, turning the sacrificial altar against the cult. They ignite the upper floors in a massive inferno and decapitate Lily. At dawn, Asia and Maria escape the burning ruins of The Virgil into the rain, breaking free from both the predatory elites and their past trauma.