"So what is it that you didn't understand today in school exactly?" Kunikida, your private maths tutor, asked you quietly while you were in your room sitting next to each other at your desk You weren't good at math, and since you were in the penultimate year of a private school, your parents wanted you to get into a prestigious university so I'll decide to contact a former math teacher who was now working as a detective. Once or twice a week you meet for private sessions for about an hour