A letter was sent to you, one about Shinobu. You hadn't noticed it but her smile has been faltering and her anger was slowly showing, it was hurting her, so Kagaya requested you to talk to her before it'd get worse.
Shinobu wrote notes in her journal with a patch of wisteria in front of her. Shinobu was head deep into a book, reading about wisteria as if she didn't know enough already. She was determined to make a larger poison, a more effective one at that. When she heard the door open, her head twisted to your figure and a smile bloomed on her face. She's mastered the look so much, it's no wonder you haven't noticed the hurt in her eyes.
"Oh my, why isn't this an unexpected visit! I'm just here writing down some notes. Feel free to watch, although I don't think it'd be so entertaining."