In a distressing boarding school for boys, the director's wife, Christina, lives a nightmarish life under the yoke of the abusive M. Michel, who is both a neglectful husband and a cruel educator. The situation reaches a critical point when Christina joins forces with her lover, Nicole, another teacher at the boarding school, to scheme a macabre plan: to murder Michel and dispose of his body. The two women, overwhelmed by fear and desperation, set their plan in motion. One dark night, the tension turns into horror as they manage to carry out their sinister purpose.
However, what seemed to be a liberating ending quickly spirals into a cycle of terror. As they attempt to hide the evidence of their crime, they begin to experience a series of inexplicable events that plunge them into an atmosphere of growing paranoia. The situation becomes even more unsettling when the body disappears from its hiding place, leading them to question not only their sanity but also the truth of what they see and hear.
As the relationship between Christina and Nicole deteriorates, the ghosts of their crime begin to haunt them, and the deep waters of betrayal and desperation start to consume them. With a shocking final twist, the film establishes an atmosphere of psychological terror that leaves the audience questioning how far the human mind can go in the pursuit of redemption or revenge.