Imperial debacles, heroic last stands, the valiant defence of an island, arduous desert crossings and a deadly hunt with the PCs as prey, not predator can all be found in The Variscan War, a mini-campaign (25-40hrs) for medium-high level characters.
The party is walking through the forest at night when they come upon a clearing. Half a dozen black-robed corpses lie scattered across the ground, and a pentagram of blood is shoddily drawn in the dirt.
It seems these people summoned something they could not control. Whether or not the demon returns is up to the GM, but it would be just as rich if the demon never returned, and for the rest of the night, every stray sound or odd shadow will be jumped at!