In a remote and strict all-girls boarding school located in the French countryside, young Teresa arrives and quickly discovers that the institution is run with an iron fist by the formidable headmistress, Madame Fourneau, whose son, Luis, lives in the manor. The school is structured to enforce discipline, where the girls face harsh and humiliating punishments for stepping out of line. Amidst the cold and regimented environment, Teresa befriends some of her fellow students, including the rebellious Irene. However, Teresa soon realizes that the school harbors dark secrets when she learns of several mysterious disappearances of students.

As Teresa delves deeper into the sinister undercurrents at the school, strange occurrences and eerie cries disturb her nights, heightening the sense of menace that envelops the institution. The unsettling atmosphere is further compounded by Luis's intrusive presence in the girls' lives, and Madame Fourneau’s obsession with perfection and control. Tension mounts as Teresa tries to piece together the puzzle of the missing girls, all while navigating the suffocating rules set by Madame Fourneau. Suspicion and paranoia grip the boarding school as fear builds amongst the students, hinting at a chilling revelation that threatens to shatter the school's rigid façade.