In an intern college, Teresita is a teenager and the only daughter of a rich couple. She starts being troubled by loud sounds and the scary visions of a tall man in black walking towards her menacingly. Soon she becomes obsessed with strange physical symptoms and visions of arms extending from the walls to grab at her, and sometimes she gets violent. Eventually, she kills her own mother but it's ruled as an accident. No-nonsense Doctor Bebeau prescribes electroshock treatment as the only way to cure the girl, but neither the lady doctor, nor the teachers at the college would listen to him. A lady doctor takes the poor orphan in, and upon their first meeting, the girl attacks the doctor and knocks her around the room. A priest is called him to try to wrench the devil out of her body.