Look Not With Thine Eyes But Thine Mind (5E)

From publisher blurb: A 5th Edition Mini-Dungeon for 4-6 PCs of levels 5-6 Deep within some hidden caverns, the PCs find a disguised door leading to a secret space that’s becoming a hide-out. With 15-ft. high ceilings, the entire area is under a permanent deeper darkness spell. It sounds like it’s inhabited.