So I finished up Kayelinth's special farm, and I noticed this cave opening behind the house. I entered it and the sign read "Dragons Lair." I went in but didn't find any dragons, just a yellow squared pad. Is it unfinished or something? I don't understand. 

Its kayelinth's request, she said she want to store her gold or something that she found in the future there...

More or less like that

You can see her request when you talk to trey? or someone to make the farm