Story : Within the Barrow.

From Ars Magica

The lack of any real sensation or effect was the strangest aspect of what happened next. Had they not been crossing over at such a place, it is possible that they could have crossed halfway though a step, and not noticed a thing until something unusual came into view.

Instead, as they moved toward the broken stone portal, toward the bank of earth behind it, they suddenly found themselves stood within a dark, cool passage. On all sides, except before them, they could feel cold, damp stone. The sound of their own breathing, and the shuffling of their feet upon stone seemed unaturally loud in the stillness of the barrow.

As their eyes accustomed to the gloom, it seemed that some faint glow came from a hole in the stone ceiling a little further down the passage, and beyond that, darkness.