I'm honestly not sure how much I have to say about Blood and Black Lace. I watched it twice, once in Italian with subtitles, and once in English. For the former viewing, the subtitles were poorly done and blended in with the background. For the latter viewing, everyone seemed to be whispering due to the disk being too scratched up for my PS2, forcing me to watch it on my computer. Finally, I just pulled up Wikipedia, and read the entry to make sure I was able to understand the plot.
The basic premise of this movie is that a model at a fashion house (Francesca Ungaro) is murdered, and the police want her diary as evidence. The other models find out that the diary reveals numerous dark secrets of the house. So the diary changes hands among people who don't want their dirty laundry coming out, and the masked killer returns to try to find it by killing and torturing whoever currently has it.
Meanwhile, we also see an Inspector (Thomas Reiner) uselessly investigating the murder. I don't think the Inspector was intended to be incompetent. Rather, I think he was supposed to believe that he was in a traditional police story, rather than a slasher film, and be rendered ineffective by that. I would compare him to the wife from Citizen Kane: not actually “bad” per say, but out of his element and his normal range of talents.
The murders themselves are effective. The director does a good job of showing the human suffering of those who are dying. This is constantly offset, however, by the fact that even having read Wikipedia, I found it very difficult to care what was going on, or who any of these people were. I never found the story of “if this diary gets out, it will create a scandal!” to be all that pressing. I'm sure that if I were in the situation, it would seem urgent to me, but obviously I'm not.
It's hard for me to say why this bothered me. Many horror films have shoe-string plots that exist only to justify the murder. But, somehow this film gave me the feeling that director Mario Bava actually expected me to care. So, on that basis, I have to say that, no, I really don't care about this particular storyline at all.
So, aside from the actual killings, I see little to recommend about this movie. If you like Italian horror, then maybe the style will be more enjoyable, and maybe you'll find the plot more interesting. Stylistically, the movie definitely reminded me of Suspiria, but without the level of style that makes the plot completely irrelevant to a viewing of Suspiria. To me though, this is just kind of a movie that exists, and that I saw.