In this current version, if you give the red stone to Nega Yuki, your scene should be interrupted by the Goddess.
I am working on a new scene that will allow you to give the red stone to the Headmistress instead. If you do this, you will not go to Nega Yuki.
Choosing to give her or not give her the stone is just a way for you to experiment with how she reacts.
We have more content coming, but it is not ready yet.
Thanks for playing!