What is about creepy children that makes them so disturbing to adults? Of course, anything creepy has the potential to be disturbing, but creepy children especially seem to have their own special power. This power has made them a recurring motiff in popular culture and imagination. They run rampant in many classic horror movies (Village of the Damned, The Omen, and The Exorcist being just to mention a few). Children belong to another world in a way, and since every adult was once a child, they can observe and vaguely remember this world without really being able understand it anymore. At least not in the same way. Also many adults prefer to view children as innocent creatures, blissfully unaware of the evil that goes on in the world, and a buffer between them and it. When this buffer disappears and children become part of that evil, it implies the world's balance is basically shot. But it's often forgotten how vulnerable children are. They live at the mercy of adults and consequently they see and experience very adult things whether they mean to or not. It's this reality that lies at the center of Henry James's The Turn of the Screw, one of the best ghost stories of all time and the mackdaddy of psychological horror.
Note: I don't give away the ending of The Turn of the Screw but I do reveal a good amount of the plot.
First published in 1898, James's novella begins with a group of guests gathered for Christmas holidays who pass the evenings telling ghost stories. One of them, a man named Douglas, produces an old manuscript and reads it aloud. It is the memoir of a young lady he once knew and tells of how she, as a 20-year-old parson's daughter, took a position (her first) as governess for two orphans living in a large, isolated manor house in the English countryside. Their guardian, having inherited them from his brother and sister-in-law who died in India, is too preoccupied with his swinging London bachelor lifestyle to take care of them himself. The job has its drawbacks--no company besides the kids, some servants, and a housekeeper; a strange rule that no matter what happens the governess must take care of it herself and not trouble the Uncle; and then there is the matter of the previous governess who died....but oh well! She takes the job, of course.