Classroom office.
Since school had just let out.
There were not many teachers or students left here, only a scattered few.
Natsume Chikage arrived with the information he had just learned and handed it to the physics teacher, Ishida Shinya.
After briefly looking it over.
Ishida Shinya said in surprise, "So that was it. I can't believe the truth was this. No wonder I couldn't find anything no matter how I tested it—it required turning on the exhaust fan, piano, and electric fan."
"I never expected your Collection Club to solve another one of the school's Seven Mysteries."
"But this time, it seemed you didn't help at all?"
"They solved it all by themselves?"
Natsume Chikage nodded. "Yes."
"They said they wanted to solve it themselves."
Ishida Shinya praised them, "To come up with physics knowledge like that, they must be very quick-witted."
"I'd guess it was Saionji Nanase and Yukimura Suzune."
"As expected of top students. They even noticed this kind of extracurricular knowledge."
"It seems they usually read quite a few books outside of class."
As he spoke.
Ishida Shinya smiled suspiciously.
"But—after you went there with them, did you really not discover anything?"
Natsume Chikage thought for a moment, then smiled and shook his head. "No."
"After all, we weren't there for very long."
Ishida Shinya replied, "True."
"But now that we know the truth, that's good. I can report it to the administration later."
As he spoke.
He muttered, "I heard they're planning to renovate that music room."
"But if turning on the piano, electric fan, and exhaust fan together causes this phenomenon—that's going to be troublesome."
"Even though it's been explained, infrasonic waves can still have a slight effect on the human body."
"It looks like the piano, fan, and exhaust fan will all need