I remember reading this book in the early to mid 1970s – gothic mystery, paperback, set in a big mansion on the coast of NC. A woman is hired as a secretary, to a wealthy man, and moves to (New Bern, NC?) to work for him, in his home. She rarely sees her boss, who has some strange rules about where she can and cannot go in the house – one of which, I believe, is a central courtyard area, where she discovers a number of young women walking around at night. At some point, she finds a hidden doorway to an elevator – an entrance to a basement harem of beautiful women who are basically being held against their will, guarded by eunuchs. When she is discovered, (if I am recalling this correctly), she gets added to the harem but eventually manages to escape. Focus was leading up to the discovery of and being held in the harem. The escape was only the last 1/4 of the story if I recall correctly.
It’s been quite a while since I read this so my facts may be slightly off. It was a really good story, badly written – but I would love to find the name of it again and re-read it. No idea who the author was or the main character’s names – Seems to me the cover was a photo of the house with the ocean behind it – maybe her in a dark red dress, fleeing the house which is up on a bluff overlooking the water. Very dark and foreboding. Any help finding this one would be appreciated. I’ve searched and searched….