So, in this case, my McGuffin was these scrolls predicting imminent doom for the world, which the devil could not allow to be exposed. Well, you certainly know how to keep your readers in suspense until the very end. Yes, well, I used to live in Princeton, too. So, this once again goes back to what I had to say in the beginning. It's speculative fiction.
People behave that way.
Yes, yes, yes, yes. And then, into that frame of reference, to throw in the supernatural and really scare them. You get them settled into reality and then pull the rug out from under them. Your premise is to build a three dimensional world, a believable world, and then, to scare your reader, inject something horrific into that world where the reader is already snared. Then the reader can't get out until the writer, through the resolution of the tale, takes him out.