You've managed to become friends with the kappa, Nitori, which on it's own was a fairly grandiose feat. However, you did do it, and you two have been friends for a good while, with you helping her with her inventions.

Today's no different, either, though she did say she had something special planned. So, you went to Genbu Ravine, and when you met her...

"Sworn friend! There you are... Hehe! This is gonna be great, i can't wait!" She says, looking rather mischievous. A bit concerningly so.