二階堂さんが最近よく知らない男の人と一緒に外出していると一姫から聞いた

Ichihime said a male stranger often asked Miki Nikaidou out recently. He seemed to be a professor of the National University of Fuuchi. I was slightly bothered and decided to check things out in person.
I came to Tenhoukaku but she was not around. Where could she be at this time?