In 1947, Padre Ricardo arrives at a crowded marketplace to investigate a string of miraculous healings performed by a mysterious child named Anghela Sta. Ana, Rhed Bustamante whose touch seems to bend reality, aided by a mysterious nun, Phoebe Walker as Sister Cecilia. Ricardo becomes uneasy as each healing is followed by a black liquid dripping from Anghela's mouth. Miguel, Ronnie Alonte, a deacon, travels to a nearby monastery where he meets Sandoval, a former priest who was excommunicated. Sandoval explains an old ecclesiastical custom: temporary deacons are secluded at the end of their training, a seven-day window believed to leave them especially vulnerable to demonic influence. During this period, Miguel encounters his fellow deacons—Carlo, Fabián, Dominic Roque, and Marco.
Inside a church, Padre Ricardo confronts a bloodied Anghela, discovering that her parents were murdered. The local bishop orders Anghela and Sister Cecilia to be housed among the secluded deacons, despite Ricardo's protests, but allows the investigation to continue. Sandoval initially resists the arrangement, warning it could disturb the deacons’ training, but he finally yields when the bishop reiterates the directive. Anghela uses her powers to restore bread that had spoiled and to turn tap water into wine; the deacons marvel at her miracles, though Miguel remains skeptical.
Nightmares plague the trainees, each reflecting a sin: Marco's gluttony that contributed to his siblings' deaths in the war-torn era, Fabián's reason for joining the priesthood as a flight from an abusive mother, and Miguel's torment by the ghostly visitation of his dead former lover, Erina, staged as a grotesque version of Our Lady of Sorrows. One night, Anghela seeks Sandoval in the kitchen for sustenance and later discusses his excommunication; she convinces him of his innocence, and he departs the next morning, leaving the deacons in Anghela's care.
Padre Ricardo returns to a convent to question the Mother Superior about Sister Cecilia. Despite the Mother Superior's rudeness, she provides Cecilia's records but warns Ricardo to stop investigating and never return. The documents reveal Cecilia's war-time trauma—she was gang-raped and left with a burned face; Anghela later heals those scars. The records also show Anghela's orphaned origins and adoption, and a startling note where the name NgaHela appears, an anagram of Anghela, said to be the Devil incarnate. The documents imply Anghela’s healing and miraculous powers derive not from God but from malevolent forces. When Ricardo tries to warn the bishop, Sandoval bursts in and shoots the bishop dead, announcing Anghela's whereabouts and that she awaits Ricardo.
As the deacons complete their training, Anghela persuades them to redeem their sins by indulging their vices, sometimes using Cecilia as a pawn. Marco succumbs to gluttony; Fabián, Dominic Roque, reveals his abusive tendencies; Carlo is shown as a pedophile. In a Black Mass conducted in the monastery chapel, Miguel tries to persuade the others to distrust Anghela; he denounces her as a false prophet and flees, with Anghela, Cecilia, and the three deacons in pursuit through the woods. A chase ends with Miguel unconscious after a fall; a flashback reveals his heartbreak over Erina, who had become pregnant but, betrayed, hanged herself after giving birth. Anghela tends to Miguel’s head wound and the revelation hits him—she is his daughter.
Back in the chapel, Anghela resumes her satanic rite while the four deacons drink from a chalice filled with the ominous black liquid. Miguel drinks, yet his doubt lingers. Padre Ricardo confronts Anghela again, attempting an exorcism, only to be incinerated by her powers. Miguel seizes Anghela away, taking her to the chapel and barricading the door. There, Anghela reveals herself as NgaHela, the demon plotting to seize control of the Catholic Church; those she has healed are now her followers. Cecilia and the deacons press against the barricaded door, but Miguel drives a knife into Anghela, and black liquid pours from her mouth as she dies. Miguel escapes, vanishing from sight.
The film closes with Fabián, Carlo, and Marco being ordained by a new bishop who remains unaware that their ordination was not to God but to the Devil.
