I would love to be able to say that I’m well-versed in American cinema, but when I really think about it, I’d be hard-pressed to name a pre-1975 film I’ve seen that doesn’t star Brando or Newman or the Marx Brothers. Though I’ve seen many of the best and worst films of the last two decades, I have little to no knowledge of B-movies or older exploitation films. To be honest, I hadn’t even heard the word “grindhouse” until Robert Rodriguez and Quentin Tarantino’s spoof of the genre—which I also never saw—came out in 2007. So when I found out that the Brattle Theatre was showing a series called “Return to the Grindhouse,” I was intrigued, not only because of my own desire for cultural education, but also because one of the films was irresistibly advertised.

“Nunsploitation’s finest hour and a half,” began the description of the 1972 film “Les Demons” on the theatre’s website; I was immediately sold. As far as I’m concerned, anyone not moved by a portmanteau that inventive clearly has no soul. Thus, late on a Friday night, I found myself seated among other eager moviegoers, most of them male, awaiting the start of a movie that would open my eyes to an unfamiliar art form.

“Nuns! Now!” yelled an impatient audience member from the balcony, and the series host ended his lengthy introduction and began this film of witchcraft, torture, and rampant sexual urges in 17th-century England. In lieu of a plot summary, which would—trust me—be absolutely pointless, allow me to mention some choice moments from the film that emphasize its key aspects.

The dialogue, dubbed in English from its original French, included choice lines like “A woman’s weeping is like a melodious modulation,” spoken by the royal Lord Jeffries while a female character is tortured. Later, the maniacal and (of course!) secretly lesbian Lady DeWinter proclaims that the nun witch Kathleen and her lover Thomas Rinfield will die “the longest death ever!” with her last syllable nearly cut off by a rapid scene transition.

The low budget effects were equally as charming, especially in scenes where the other nun-witch-sister, Margaret, gets revenge on those responsible for killing her mother. Her newfound dark powers enable her to kill anyone by kissing them, but instead of her victims simply dying, they immediately become skeletons—skeletons with hair.

But the heart of the movie lies in its sex scenes, of which there were many. I’m pretty sure Kathleen—that’s the first nun-witch—sleeps with every male character in the film, and her sister Margaret added two female characters—and the devil incarnate—to their final tally. (To quote a friend, “Those nuns got mad ’sploited.”) These uncomfortable encounters included shaky camerawork as the handheld camcorder filming the scene zoomed in and out unexpectedly. But the highlight of each scene was the music: an amazing and hilariously malapropos soundtrack that sounded something like a Clapton-fronted Mariachi band.

There is, however, more to the experience of watching “Les Demons” than simply what appears on the screen and rumbles through the speakers. Jesus Franco, the movie’s prolific director, has a reputation for being basically the Robert Pollard of cult filmmaking: he’s produced hundreds of passable films and a handful of great ones—or so I’m told. And though “Les Demons” may not have been one of his fabled greats, his ability to entertain was apparent in the audience’s enthusiasm at the Brattle that night.

From the scattered laughter at the film’s awkward scene transitions to the shouting and clapping every time Margaret turned a victim into a skeleton, the audience was engrossed by the film. Whenever a male character wanted to “privately question” a female character, the audience reacted with knowing chuckles and a mutual “Yeah!” Each moviegoer was actively involved in everyone else’s viewing, an element I found to be as essential as the movie itself during this particular cinematic experience. Sure, audiences sometimes laugh or cry, but the palpable excitement during the movie was something altogether different. Watching “Les Demons” may not have provided me with a shining example of time-honored film artistry, but my experience was nonetheless valuable, as the “Return to the Grindhouse” ushered in a sense of community I’d never before witnessed at the movies.

—Columnist Jeff W. Feldman can be reached at jfeldman@fas.harvard.edu.