After a few hours of travel during which the captives kept staring at Aster, Espi finally reached a tall rock formation, which indeed matched the description of "Dry Cascade".
"Stop, take us there", Aster tapped his hand on Espi's head, and ordered it to take them near the dry cascade.
Even from up-close Aster couldn't see nor feel any kind of entrance or formation engraved in the rock, but since he has come all the way here, then he might as well give it a try.
"Let one of them go Espi".
Espi nodded and then released the captive who talked with Aster earlier.
"Don't try anything funny".
The captive nodded, and then slowly approached the rock formation before he cut the tip of his index finger, and after drawing a few strange characters, which Aster recognized as an old variation of runes.
The ground trembled for a split of a second, making Aster and the girls raise their guards, but ultimately, they weren't ambushed unlike what they expected.
