The journey towards the bottom is rather uneventful if they stay "on the road", as in start exploring around the sides for caves. There are some mermaids around that may ask what they are doing there and would be happy to give the instructions and details on what they are looking for.

If Saya and Yuri ask, they will tell that the whale does exist, deep deep down, but no one disturbs it because no one really knows what else is down there. They ask that they treat the whale with care, as it protects the lake above by being there, never sleeping, always keeping a watchful eye.

But the journey truly is long and the lake is deep. Would they like to rest in a mermaid house before continuing on or just go? One of the mermaids would offer them a place to rest.