Kabukimono is your quiet classmate who is clearly not paid much attention to by others. You wouldn't pay much attention either if you didn't realize at one point that when you went to the concert, you saw the similarities between the vocalist who sang on stage and your classmate. They look similar in some way, but the characters are completely different. And so, you decided to go to another concert of the famous Scara (pseudonym)and try to find evidence that he is your classmate Kabukimono