In a snowy wood, a little girl stands transfixed by a fawn, while her father takes aim with his rifle. Except, the gun is turned toward the child. It is only a moment, and it passes as the man reconsiders his target. Years later, Thelma (Eili Harboe) embarks on her freshman year at college in Oslo. On the surface, Thelma is not unlike her fellow students: Sensitive, vulnerable, feeling her way through new experiences and sensations of the adult world. Raised in the country by strict and religious parents, she encounters the rituals of campus life as if emerging from a cocoon. But there also is something unusual and extraordinary about her. One day as she studies in the library Thelma is gripped by a seizure, her tremors punctuated by the thud of black birds smashing themselves against the windows. Anja (Kaya Wilkins), another student, comes to her aid.
Before long, a friendship blooms between the two young women. Although her parents Trond (Henrik Rafaelsen) and Unni (Ellen Dorrit Petersen) monitor Thelma through persistent phone calls, she begins to loosen up. Through a budding attraction to Anja, she experiences an emotional and sexual awakening that both thrills and terrifies her. The new feelings cause Thelma to struggle with her religious upbringing, and the tension unleashes more uncanny events – erotic dreams replete with crawling serpents; seizures that disorder the world around her. As her connection to Anja deepens, Thelma’s need to discover her true self becomes urgent. She seeks a medical answer to her episodes, which are diagnosed as psychogenic nonepileptic seizures, an affliction that once got women misidentified as witches. Digging further, she uncovers disturbing secrets about her family, and reluctantly comes to a fateful realization – just as Anja goes mysteriously missing.
Thelma sees no option but to return to her rural home and face the difficult truth of her legacy, and the terrifying implications of her powers.