Somewhere high in the mountains, where the air is thin and the trails are buried under ice and snow, a massive waterfall plunges through a deep narrow gorge. Halfway up the falls, spanning the gorge from wall to wall, sits a stone keep on a natural bridge of rock. It is not on any map the party has seen, and the locals in the valley below speak of it only in whispers. A powerful frost giant has claimed it as a stronghold, and something the creature is doing up there is corrupting the falls. The water running downstream has turned foul, poisoning livestock and sickening anyone who drinks from the river. The valley villages are running out of time.
Getting to the keep is half the challenge. The gorge walls are sheer and icy, the trail switchbacking up the mountainside is treacherous in good weather and nearly impassable in the current conditions, and the falls themselves fill the gorge with freezing mist that coats every surface in a fresh layer of ice by the hour. The party will need to manage the environment as carefully as they manage any combat they encounter along the way.
The keep itself must be destroyed from within. The party has been given a powerful magic item capable of bringing the structure down, but using it means they’ll need to get out before it does. Finding an escape route in an unfamiliar stronghold, under pressure, in a blizzard, with a frost giant somewhere in the building, is the kind of problem that requires more than a good sword arm.
Party Level: 9-12. The environmental hazards, the frost giant, and the timed escape sequence make this a genuinely punishing adventure for underprepared parties.
World: Any
Rules-set: OSR or 5e
If this made your session better, buying me a coffee keeps the Vault stocked.
