Killer Nun is a 1978 Italian exploitation film directed by Giulio Berruti, often classified in the "nunsploitation" subgenre. Starring Anita Ekberg as Sister Gertrude, the movie unfolds in a convent where Sister Gertrude, once a compassionate nurse, begins to descend into madness following brain surgery. Addicted to morphine and showing signs of erratic and violent behavior, she becomes involved in a series of mysterious deaths within the convent. As suspicions mount, the line between sanctity and depravity blurs. Noted for its controversial content, Killer Nun is a lurid look at the dark side of religious devotion. The movie is loosely based on a true story of a murdering nun.
(Summary by FreeGreatMovies.com)