Another Horror Plot

What makes for good science fiction horror is how close, but not quite, it is to reality. Handmaids Tale is the genre I'm thinking of. Here's one:

The world has seen the rise of a charismatic, almost messianic, set of right wing leaders whose followers have a religious fervor and a curious ability to tune out reality that doesn't fit what their leaders tell them. All of these leaders seem like puppets of *something*, but no one knows what. People who are immune to the cult's siren song, or are "undesirables" have started disappearing or turning up dead in gruesome ways. Our intrepid, frightened heroes have to figure out how to break the spell before they get dead.

To real? Or a great thriller?