I watched this on Mondo Macabro's DVD of it, and the picture quality is very good - nice and sharp and colorful. For some reason it is a little scratchy in the last few seconds (perhaps appropriately enough, since Old Scratch himself is appearing at that moment).
A young pretty nun is wandering through the countryside picking flowers. She sees a naked man who greets her, and she runs away. When talking to a local boy, the man reappears in clothing this time, and he tries to get her to take a bite of a shiny red apple. She runs away again, and the devil (as he clearly must be) takes a bite of the apple while he watches her retreat.
The devil shows up against outside the convent window when the nuns are eating. He disappears, then appears as a small red thing (light, jewel, apple?), then even that disappears. The nun shows herself to be kind to the black nuns, who are discriminated against, and to be gentle and healing with animals.
When another nun comes to her room to declare her admiration and love for her, she immediately collapses on the bed accepting the seduction. Satan finally got to her. Her behavior becomes more satanic, as she seduces or kills people. Her clothing is frequently removed. Satan proves himself to be pretty powerful, while God seems absent.
The ending might have been a concession to censors, I'm not sure. There are a lot of nice extras on the DVD, including a short overview of nunsploitation and an essay on the subject, among other things. I haven't seen many such movies myself, apart from some weird nun movies like Alucarda, Dead Waters, and Demonia - hardly typical Catholic nuns.
