The VOIDRUNNER'S CODEX is coming! Explore new worlds, fight oppressive empires, fend off fearsome aliens, and wield deadly psionics with this comprehensive boxed set expansion for 5E and A5E!
I know this is a little bit back, but this adventure seems to fit your description. A secret cult operating within a slaughterhouse. An adventure designed for parties level 7 to 9.
https://cultadventures.com/product/marked-for-slaughter/
The VOIDRUNNER'S CODEX is coming! Explore new worlds, fight oppressive empires, fend off fearsome aliens, and wield deadly psionics with this comprehensive boxed set expansion for 5E and A5E!