"The Innsmouth School for Girls" follows Roberta Olmstead, a young woman seeking a fresh start after a troubled past. She discovers the enigmatic Innsmouth School, situated in a coastal town shrouded in fog and myth. The school promises a unique education, combining traditional studies with the exploration of the esoteric and the unknown.
As Roberta settles in, she becomes aware of the school's strange and secretive atmosphere. The faculty, composed of eccentric and enigmatic figures, seem to have their own hidden agendas. The headmistress, a formidable woman steeped in mystery, enforces strict rules that the students must adhere to, yet there's an undercurrent of allure drawing Roberta deeper into the school’s secrets.
Throughout her time at the school, Roberta forms friendships with other girls, each harboring their own stories and secrets. They soon discover that the school holds dark rituals and occult practices, intertwined with the town’s sinister history. The plot thickens as they stumble upon libraries filled with ancient texts and artifacts that hint at the school's connection to the sea and mysterious cult-like practices linked to Innsmouth's past.
Roberta starts experiencing vivid dreams and visions, leading her to question her sanity. She uncovers the truth about the school's relationship with deep-sea entities, and the girls are faced with choices that could reshape their destinies. Tensions rise among the students as they confront the headmistress and the staff, who are determined to fulfill their mysterious goals.
As the story unfolds, Roberta must navigate a web of deception, bravery, and the supernatural, ultimately leading to a confrontation that tests the bonds of friendship and the limits of trust. By the climax, Roberta faces a crucial decision that could either free her and her friends or bind them to the school's dark fate forever. The film blends elements of horror, mystery, and coming-of-age themes against a backdrop of Lovecraftian influences, leaving viewers intrigued and haunted by the story long after the credits roll.