Nemuro Memorial Hall - S1.E22

There is only one black rose left now. Akio is wondering if Mikage will finally fight Utena himself. But instead of fighting, Mikage decides to include Utena in his side, and asks Utena to join his Mikage Seminar, but Utena turns it down. Mikage talks about Nemuro Memorial Hall, where Mikage now holds his seminar. Decades ago, there was a professor called Professor Nemuro, who was doing some research at the hall. One day, there was a fire, and the hall burned down, which took away 100 lives of his students.