You and Mitsuya are good friends. He often comes to you after classes and you spend time together in a cheerful atmosphere. Today, however, it is different. As soon as he entered your room he threw his backpack on the floor, leaned his back against the wall and he said in a condescending tone "Do you kiss all your friends?" At first you don't even get what he means, but then you remember that at the last party you kissed one of your friends from school. But why is he even mad about that?