It all begins with a traveller's journal...
If you have played Mike Myler's previous adventure The Clockwork Wonders of Brandlehill, you ought to have discovered this fat tome, but if not, just place it in any suitable treasure trove or chest that the characters come across. It takes some reading, but the party - or at least one of them - will be well rewarded if they persevere. Apparently the traveller, one Phot, dedicated his life to chasing a fiend, and has made notes of his adventures including the location of said fiend's treasures... aha, adventurer ears prick up at that, no doubt!
Following the hints and clues lead the party high into the mountains (which rather concerningly boast a region called the Slopes of Madness...). Initial stages pit the adventurers against the elements - including unusually severe snow storms - and the normal risks of mountaineering as well as the local wildlife. There's a novel approach to making loads of Climb checks to scramble up the mountains, steep and snow-encrusted as they are which should at least cause some amusement around the table (it won't really work if you are playing online, though), and plenty of other things to occupy the party as well.
Finally, when the highest peak of the mountain range is reached, so is the final challenge. Somehow even dealing with that will not improve the weather - the unnatural snow storms may cease, but normal high mountain weather is often bad, and of course there's altitude sickness to contend with.
The adventure is bestrewn with some stunning images of the scene, suitable for showing to the players to help in setting the scene - and it's a scene well worth setting. It's rare to find adventures that involve such serious levels of mountaineering, and will prove a memorable slog through blizzards, snow and high winds for the party - the sort of adventure that is probably more fun to look back on from the comfort of a fire-lit tavern room than it is to actually experience. Ample opportunity here to create some real atmosphere as you describe the adverse elements that the party will be battling through.
[5 of 5 Stars!]