The book starts with a bunch of friends gathered in a house/mansion telling ghost stories to entertain themselves.
The ghost story that the book is titled after is told by one of the guests, Douglas, after he has someone fetch the original manuscript written by an unnamed woman from his residence.
Douglas describes the story as "beyond everything [...] for [its] general uncanny ugliness and horror and pain". And that's probably the most accurate description of the story.
The Turn of the Screw is told from the perspective of a young governess employed to teach and take care of two children, the 8-year-old Flora and the 10-year-old Miles.
Obviously, just based on the first sentence of the book, this is a ghost story. But the real horror of the story is not the ghosts, but the narrator herself, the governess.
There's so much to be told about her, but that would be spoiling the story. But just as her opinion and attitude towards her charges, the children, fluctuated through the story, so did my opinion of her.
Everything aside, I found her obsession with these kids disturbing. From the moment she sees the girl, she describes her as "a creature too charming not to make it a great fortune to have to do with her," and "the most beautiful child I had ever seen," and she literally loses sleep that night because she can't stop thinking about her??
She holds pretty much the same opinion, yet somehow even more exaggerated, about Miles, but the most disturbing instance of her with regards to him, in my opinion, was in the final scene, where she describes a moment of silence between her and the boy like:
"We continued silent while the maid was with us – as silent, it whimsically occurred to me, as some young couple who, on their wedding-journey, at the inn, feel shy in the presence of the waiter."
This simile is bad on its own - she's likening a 10-year-old boy and herself, a grown woman, to a couple on their honeymoon - but it's even worse when you remember that earlier in the story, once the governess expresses her concerns about this little boy possibly "corrupting" others in school, Mrs. Grose, the housekeeper, (half) jokingly says, "Are you afraid he’ll corrupt you?"
Again, she's talking about a 10-year-old boy!
There's just so much going on with her in this story. Her actions, her self-righteousness, her delusions, her cruelty, and the way she justifies them...
And that ending... I audibly gasped. I don't know how I expected the story to end; I definitely didn't expect a happy ending, but I also didn't expect THAT.