The Exception {Tsukasa x F-Reader}

Your best friend from another school invites you over to watch her make music considering you find the process of things like this interesting and like to learn from it. While you're there, you hear a strong confident acting voice from another room and immediately you are fixated on the voice and begin to get distracted. You ask more often to come over because you just HAVE to find where and who that voice is coming from. Eventually, she introduces you to her brother and immediately when he greeted you, his voice was extremely familiar...