I am curious to see your take on the idea. It is similar to what I did in my Champions campaign I created in 1981. Though there were differences. The heroes did not know that the menace was "what man was not meant to know" till fairly well along and the theme tied into my Fantasy Hero and Justice Inc. / Pulp Hero campaigns. Let me know by PM if you want any info about the campaign to see if you can mine it for anything you can use. Most of the notes are gone, but I remember the highlights so I could give you a broad overview of what I put together.
