I had never seen this before, and I've always been a Tom Selleck fan (as well as a horror movie fan) so when I saw TCM was airing this movie I had to record it!
I watched it the next day....and throughout most of the movie I was actually intrigued, despite the 70's cheesiness and silly plot. There's actually an "art" to B-movies (usually horror or scary in genre) from the 70's and "Daughters of Satan" was actually pretty awesome. I was even considering buying the DVD...which is available.
However, the ending "sucked" so bad (in my opinion) that it ruined the rest of the movie for me!

I don't want to include spoilers, for those who haven't seen this movie yet, but how the film concluded ticked me off enough that I didn't keep my recording...and I will not be buying the DVD!
