A mega-dungeon that supports a full-year campaign. A legendary adventure considered by many to be one of the greatest of all time! Explore a thousand-year-old dungeon mystery waiting to be solved...

When the anomaly appeared at the Earth's core, the Substratum Protocol was initiated. You are the best and brightest scientists we have left, our last hope to stem the apocalypse. You are the Substratum Expedition Team. Descend. Learn. Survive.