A dark conspiracy is afoot. An unnamed but sinister organization, visible only through patterns in seemingly unconnected events, deaths and atrocities, has a nefarious plan to use primitive rituals waken an ancient evil and subjugate the Earth to their immoral ways. Or perhaps the cultists are in touch with an alien race keeping the rest of the population in the dark while they prepare to sell our culture and our planet for some obscure, but certainly not pleasant, purpose. Or an ancient organization that has existed under the surface of our civilization for millennia plotting against the best interests of humankind is risking making itself visible now that they are so close to achieving the ends toward which they have been working for so long and winning supremacy over the whole race.
Depending on who you listen to (HP Lovecraft, The X-Files, Dark Angel, etc.) these secretive occultists are counter-cultural degenerates with no morality who will wittingly or unwittingly destroy humanity if we don’t stop them; corrupt members of the military/political establishment who abuse their power and are almost unstoppable; a élitist and anti-social guild or clan who have hidden from both traditional and liberal society because their membership is tightly restricted and their agenda inimical to reactionary and revolutionary alike.
But in other stories the occultist underground is a positive movement, a force of secretive protectors of humanity, knights against injustice, or countercultural pagans using their arcane powers for good. (Or in a less clichéd way, just doing good but keeping hidden because of the distrust society has for non-mainstream practices/faiths.)
As I think I’ve shown (and I’ve barely scratched the mirror) there are a lot of social-political issues that can be addressed in stories that use occultism and secret organizations as a theme. Like Lovecraft, you could use the theme as a vehicle for your xenophobia and puritanism; like Dick you could use it as a delivery system for your paranoid mysticism; you could use it as a thinly veiled assault on Freemasons, Kabbalists or Vouduisants, on bankers or the military industrial complex, on scientists or environmentalists. I’m sure many of these things could appear in (or lurk under the surface of) a very good, readable and entertaining story.
If The Future Fire is going to consider your story about occultists, however, the usual rules apply. As well as beautiful writing, and a gripping plot with believable and engaging protagonists (whether heroes or villains), and intelligent scene-setting and premises, we want to see stories that questions rather than reinforce the lazy prejudices of their readers, that challenge the worst excesses of the reactionary and that promote understanding and social justice rather than fear, persecution and greed.