The underground river carried them forward. The water flowed through winding passages that slowly became wider and smoother. Naviga noticed the change first. The rough, natural stone walls were turning into surfaces that looked almost polished. At first, the difference was small. It was easy to think it was just the dim light from their essence playing tricks. But as they went further, the change became clear.
"Miss, the walls are different here," Naviga said, pointing to the shiny surfaces around them. "This does not look natural anymore."
Minerva stopped. She reached out her hand to touch the closest wall. Her fingers met something cold and very smooth. "You are right. This is ice, but not like any ice I have ever seen. It feels almost like glass."
