A priest is sent to a convent to investigate the sheer lunacy of a bunch of nun's gone nuts performing acts of lust and depravity. But the closer he looks into the situation the more supernatural it becomes. Does the devil roam the halls terrorizing the nuns or is it something a bit more sinister.
I'll get Mattei credit; he tries to inject a little something more in your average, ordinary (nunsploitation storyline (if there is such a thing). It's not entirely successful in that regard but never-the-less he manages to pull off this entertaining but a little slow and the bit of a Stephen King twist to the ending helps it out.