In the shadowed corridors of a cloistered convent, a young nun named Sister Cristina becomes lost in the labyrinthine catacombs while searching for Sister Assunta Paola Montenero. Her desperate trek leads her to a dim space that resembles a hidden laboratory tucked away in the convent’s morgue, where the air is heavy with secrets and unease. There, Sister Assunta is busy preparing a nun’s body for embalming, and the atmosphere hums with warnings about temptation and the danger of lascivious desires that threaten the order.
Sister Assunta’s grim monologue hints at a brutal history: an echo of a child born inside the walls of this very place, conceived by a nun who consorted with the devil, and the disturbing events surrounding the murder of the previous mother superior, Sister Fiorenza Alba Maiolini. She insists that Sister Fiorenza’s ghost still stalks the convent, calling out the name of the nun who killed her. Then, as if under a supernatural compulsion, Sister Assunta brutally murders Sister Cristina before dying herself, leaving the air thick with fear and unresolved accusations.
Mother Vincenza Franca Stoppi soon discovers the grisly scene—the bodies of the two nuns—and tries to frame the deaths as accidents to Father Inardo Andrea Aureli. Yet Sister Rosaria Susanna Forgione vehemently rebukes the idea that human malice alone explains the carnage, insisting instead that a devilish force has taken up residence in the convent. Her claim is underscored when, after Father Inardo administers communion, she bleeds from the mouth and later experiences the stigmata behind the locked doors of her room.
As the supernatural tension escalates, Father Inardo, the Mother Superior, and the rest of the community move to purify the cloister, but they are interrupted by the anguished cries of Sister Rosaria. They rush to her chamber to find her murdered, the bed and walls stained with blood, and the atmosphere thick with dread.
To uncover the truth, the Bishop Tom Felleghy and a new, determined set of leaders turn to a young priest of their own—Father Valerio Carlo De Mejo—charging him with a thorough investigation of the convent’s darkest corners. When Valerio arrives, he finds that the recent years have been marked not only by deaths but by a series of unsettling, inexplicable phenomena that point to a much older, hidden history. His investigations quickly put him at odds with Mother Vincenza, whose grip on the monastery he begins to question as more secrets surface.
The plot thickens with the revelation of Elisa Francesca Carmeno, Mother Vincenza’s illegitimate daughter, kept away from prying eyes in a sealed room with a disfigured face. A haunting flashback reveals that, at birth, the child survived an attempted disposal after an earlier abbess—Sister Fiorenza Alba Maiolini—cast her into a cauldron of boiling water. The infant’s astonishing telekinetic strength enabled her to frighten off Sister Fiorenza and cause her to murder herself in a frenzy of fear. Now a teenager, Elisa wields her supernatural powers to punish those who learn of her existence or defy her mother’s strict rule.
Valerio slowly pieces together the truth: Elisa is the catalyst behind the convent’s brutal deaths, using her mind to bend fate itself. The discovery shakes him to the core, and the investigation takes a dangerous turn when Mother Vincenza attacks him in a fit of rage. In a chilling confession, she admits she has made a pact with the devil and that Elisa is the daughter of Satan herself. Elisa attempts to intervene to save Valerio, but Vincenza strikes from behind, intent on erasing the threat she feels. A brutal struggle ensues through the corridors, into the catacombs, and down to the morgue, as mother and daughter collide in a confrontation that tests the very boundaries between faith and supernatural power.
The clash ends with Elisa retaliating against her mother in a final, decisive moment. Vincenza pleads for forgiveness, but Elisa’s powers unleash a deadly force that ends the conflict—Elisa kills her mother, and then, in a nightmarish twist, revives a corpse to strangle the former nun. The carnage leaves both Elisa and Vincenza dead, but Valerio’s ordeal continues as he lies hospitalized, his mind fractured by the horrors he has witnessed.
In the wake of these events, ecclesiastical authorities who arrive to inspect the convent uncover more than a crime scene: they discover the laboratory-like morgue where Mother Vincenza pursued her black-magic experiments. The air remains thick with unearthly energy as they attempt to reconcile the visible carnage with explanations grounded in faith. A final, eerie image lingers as the bishop holds the cold corpse of a nun, a stark reminder that the convent’s horrors may have more to reveal, even as calm appears to return. The story closes on a chilling note, suggesting that some forces, born of pride and dark pact, refuse to stay buried.
