This scenario for Mansions of Madness requires Forbidden Alchemy.
The Mines of Yuggoth has a strong theme and a solid story, 3 small boards (instead of 1 big), exciting new mechanics, new tiles, leave a lot of freedom to the investigators, has non-linear clues, is replayable with 3 objectives and 3 different starting spaces and has been heavily playtested by several groups (around 15-20 times). Make sure to print all files with 100% (especially the tiles and cards).
The excellent english wording is the magic of the amazing talent of Randolf Carter, who I won't be able to thank enough for his help. The scenario is also available in french
(original version), russian
(with amazing special design thank to gamerxx) and german
(thanks to ecto).
If you enjoyed playing this scenario, you can try my other scenario: The Esoteric Order of Dagon