Imagine a world where 3/4's or 9/10th's of humanity have perished in a plague. Vast tracts of formerly human dominated land have reverted to wilderness. Villages, towns and castles, once epicentres of human activity have been occupied by orcs, kobold and the like. These races although similarly decimated by the plague are fecund, outbreeding the more slowly rebuilding remnants of humanity.

Generations after the plague has died out (except for some isolated pockets) humanity is once again pushing to expand its borders as newly emergent kingdoms seek prestige and more importantly treasure to grease the wheels of commerce.

Those bold enough to penetrate the border marches to secure new regions are generously rewarded with land and power. One such party of adventurers has elected to cross over the border to capture the crumbling ruins of a great castle, its history now long forgotten ...

Reaching the castle, they find the ruins garrisoned by a tribe of orcs. The orcs and their kobold servitors are lax, believing the location of fortress sufficiently distant from the border to be safe.

After disposing of the orcs, the party members find an extensive dungeon beneath the central keep. In the course of clearing the upper levels they find that the castle was once the stronghold of a powerful sorcerer (the magic of the ancients now largely lost).

Eventually with the aid of some hastily scrawled messages (nearly obliterated by decades of orc graffiti) referring to a underground chapel, they will find their way via a secret door, down to the unexplored depths of the complex. Here they find a mystery.

Numerous passageways are blocked off by smooth and obviously unnatural sheets of stone. Careful mapping will reveal that all the sealed tunnels enter a central hall or suite of rooms.

Curious the adventurers will find someway around the seals, by magic, or by digging through the walls.

On entering they find themselves in a massive hall carpeted with the bones of the dead. Dark stains on the rock seals, shattered wooden pews and waves of skeletons clumped together with twisted and broken finger bones reveal their last desperate attempts to escape the tomb they found themselves within.

At the far end of the hall more skeletons are laid out on makeshift stretchers before an altar, which is surrounded by scores of skeletons piled on top of each other, each with its arms outflung to touch the sanctity of the altar in what must have been their final moments in life. In the bony embrace of one is shattered collection bowl, overflowing with coins. An examination of which will reveal that the coins date back to or before the era of the great plague.

In the chamber of the dead, the party will have to weigh up the possibility of whether the plague is still alive in these bones, which have been cold for many a decade. Infected or not, unexplored passages and rooms lie ahead, awaiting exploration, and perhaps a cure might be found here.

Pressing onward the party will encounter a series of storerooms, armouries, sleeping quarters and so forth; the inhabitants of this castle were clearly well prepared for a siege.

All the rooms prove to be empty of life, and at last, far beyond the chapel and its morbid contents, they will come to staircase which winds down many steps to a new level.

As they move through more empty chambers, this level will seem similarly empty. But just when they are beginning to despair, they will come across evidence of occupation, mounds of hastily stacked papers overflow chests, leaking sacks of food stuffs, tuns of wine, and a vast assortment of other esoterica are piled haphazardly in rooms and corridors. Rounding a corner, they come face to face with a mummified head, still cradled in the loop of a noose hanging from an iron ring in the ceiling. The mummified body broken off at the neck and the kicked over stool tells its own story.

A door not far down the corridor opens up onto a large room, backed with velvet drapes displaying large heraldic emblems, with tall iron braziers before. But all eyes will be drawn to the round table and the frozen tableau of 12 mummified figures seated around it, tied to their chairs in some ghastly jest. One, from his princely clothing and long withered beard, perhaps the magician himself, has been strangled with his own medallion of office.

In a private room adjoining they will discover a journal, in it they will find the harrowing account of the last days of the plague, of how disease overwhelmed the overworked clerics and how as a desperate last measure, the magician lured his own people into the subterranean chapel and then sealed it off, so that the contagion might be contained.

The journal ends in a curiously upbeat note, stating that they have supplies for a year, the group is settling in well, and that they plan to eventually return to the surface, when the scourge of the plague has passed.

If the party has not removed the mummified head from the corridor outside, it will come sailing through the doorway, and bounce across the table top. From the darkness outside will come a mocking laugh. As the party scramble for their weapons, drums and war horns are heard faintly from above. The orcs are returning, and in greater numbers.