From the introduction:
The heroes have accomplished their first goal, and delivered an Eberron dragonshard of great power to their employer, Tophran Damilek. Now they seek a second dragonshard, a Siberys shard, on behalf of their wealthy patron. Siberys dragonshards fall from the Ring of Siberys that forms a broken path across the night sky. A pulsating swirl of golden veins glows within the crystalline depths of a Siberys shard. These shards are greatly coveted by the dragonmarked mercantile houses that dominate the economic life of Khorvaire, for their inherent properties enhance and focus the spell-like abilities derived from dragonmarks.
"The dense foliage of the jungle seems to part, revealing the crumbling ruins you have been seeking. After delivering the Eberron dragonshard to your patron, Tophran Damilek of Sharn, you began your search for the second shard—a Siberys shard rumored to lie within these ruins. You sailed from Sharn over a month ago, traversing the dangerous straits of Shargon’s Teeth to reach the wild jungles of Xen’drik. For days you have trekked through the trackless jungle. At last your destination lies before you.
"An enormous set of stairs rises from the jungle floor to a mammoth entry hall lined with gargantuan stone pillars. Alongside these stairs, a long flight of steps carved to a more manageable size climbs to the massive stone platform. To the left of the entry hall, adobe huts stand piled atop each other, as if the giants that built this structure had shared their living space with companions or servitors closer to your own size. These huts are jumbled together in a structure resembling a beehive, in at least four vertical layers between the great stone platform and the crumbling ceiling above it, though the upper layers appear decrepit and unused.
"As you study the ruins before you, humanoid figures emerge from the huts, seeming like ants dwarfed by the structure beneath their feet. You realize instantly that these are drow, the mysterious dark elves of this lost continent. Their night-black skin is laced with white scars forming striking patterns across their faces and chests and down their limbs. Their white hair is woven into tight braids tied back from their faces. Three figures wear light helmets and armor apparently formed from the chitin of some monstrous scorpion, complete with long, curved tails arcing behind their heads. The fourth figure wears a cloak of sorts, apparently assembled from hundreds of tiny dead scorpions."