In a dark convent in Mexico, two young women inhabit a world where innocence and sin intertwine in unsettling ways. When the enigmatic Justine arrives at the institution, she becomes immersed in an atmosphere thick with mystery and seclusion. Justine, with her insatiable curiosity, quickly finds herself drawn to Alucarda, an intense and fascinating girl who leads her to explore the boundaries of faith and morality.
Together, the teenagers unleash a series of supernatural and disturbing events: dark rituals, demonic possessions, and encounters with forces that defy human understanding. As their friendship deepens, so do the dangers they face, plunging them into a world of madness and despair. The tensions between freedom and control, the earthly and the supernatural, lead Justine to question her faith and the nature of her relationship with Alucarda.
As the convent becomes invaded by a malevolent entity threatening to consume them, the struggle for the soul and life of both young women intensifies. Their choices become a duel between the sacred and the profane, challenging the beliefs of those around them. The oppressive atmosphere of the story manifests in every corner of the convent, turning every whisper into an echo of despair. In the end, the humanity of the protagonists confronts its fate, opening a door to horror and redemption.