From the publishers blurb:
For use with Old School Essentials/ other OSR rules THE RUINS CALL. For weeks, your expedition has trekked through the overgrown jungles of these islands in search of antiquities. At last, you reach the crumbling ruins known locally as "The Sunken Sisters" - named for the twin weathered statues guarding the entrance, draped in vines. What looks like a massive stone door once barred entry into the shadowed interior. But it has long since fallen, leaving an unbroken gloom within that puts your torches to shame. A darkness that raises more questions than it answers. What civilization erected such monolithic stonework here, only to become lost to the ravaging jungle? You've heard legends of an ancient apocalyptic event known as the Atuang (Sky Fire) that reshaped this region - could that cataclysm be the key to unraveling this archaeological mystery? More importantly, are you prepared for what primordial secrets or perils may lurk unchallenged in the lightless nadir of this forgotten temple complex? One thing is certain - those depths were never meant for the unprepared. Venture inside at your own risk and solve the enigmatic riddle of The Sunken Sisters...if you dare.