A prequel to the 2017 film Verónica, the plot follows the paranormal experiences of a novice (Bedmar) enrolled as a teacher in a convent operating as a girls school in 1940s Spain.

Ten years later, novice Narcisa arrives at a convent that has been reformed into a school for girls following the Red Terror during the Spanish Civil War.

[2][3] Narcisa is greeted by Sister Julia and the Mother Superior; the latter of whom is enthused to have the "holy girl" from the news who inspired the community among their ranks.

The Mother Superior explains to Narcisa that she will take over the duty of lecturing the girls, which had previously belonged to Sister Inés, who had earlier left the convent.

Frantically searching the convent for her student, Narcisa has a disturbing paranormal encounter in the confessional booth before finding Rosa hanged behind the lattice.

As the eclipse blinds her eyes, Narcisa goes into a trance and witnesses the plunder and sexual violence that befell the convent during the war.

[9][10] The Monastery of Sant Jeroni de Cotalba was chosen as shooting location to portray the school and convent where the fiction takes place.

[19] Miguel Ángel Romero of Cinemanía rated the film 4 out of 5 stars, underscoring Plaza's consolidation as a master of Spanish horror cinema as a verdict.