From the publishers blurb:
An ancient cave found, lost, then found again holds the key--or perhaps the lock--to an emerging apocalypse that reaches through the void of time. Do those entering the cave control the world’s destiny or are they puppets playing their part in some great design? Dare they disturb the secrets lying within the Mines of Yeblith-mau?
The Mines of Yeblith-mau is an add-in adventure for 6-8 characters, levels 2-4 and playable in just about any fantasy setting. The adventure is for use with basic/expert-styled OSRs and contains descriptions of a cavern complex, two dangerous new monsters, four intriguing non-players, and five fantastical new items for your fantasy setting!
Please note that green text in the preview indicate internal document links within the PDF copy. The text is black in the printed version.