“ A supposedly empty desert on the far side of the mountains has started growing. No one knows why. At the center of the desert lies a tall rock outcropping, hundreds of feet tall. Dust storms shroud the outcropping constantly, except for one night a year.”
“ Whilst exploring underground the PCs discover tube like tunnels stretching for miles, upon further inspection the strange tunnels seem to connect all major cities in the are, what is their purpose?”