I read a gothic novel about 20 years ago but I cannot remember who wrote it. The title was something like The Dance Macabre. It was about a woman hired to be a governess or something in a household where the baby was a demon child. If anyone has ever read this book, I'd like to know who wrote it and if she wrote any more gothics.
If you are talking about the book, that I think you are it is actually "Danse Macabre" by Stephen King. You should check this out to see if this is the book you were referring to.
The book that you are describing sounds a lot like The Turn of the Screw by Henry James. It's about a governess who is supposed to be in charge of 2 children. She ends up believing that the children are conspiring with 2 ghosts. It's a pretty decent book, in my opinion.
It has been over 20 years, but I distinctly remember the title as being "Dance Macabre" although it probably was spelled "Danse Macabre". I thought it was written by a woman. However, I will check out the Stephen King book and see. The story was about a boy (a toddler) who was actually the devil incarnate and he ruled the household. The governess was not aware of this until near the end. She was responsible for his older sister.