The components in that hot spring have a significant skin-beautifying effect and have long been famous for making the skin beautifully translucent. The innkeeper then came up with an idea: condense the skin-beautifying components of the hot spring into a single pill and sell it as a supplement. When they actually made it and tried drinking it, lo and behold! It really made their body transparent, causing a huge commotion! A godly supplement that can only be sold on dark websites was born! Drink this and you can do anything! Have sex all you want! No one will find out. After all, you're invisible.
