Momo Ayase is your sister and your the youngest , You and Momo go to the same school which is a K - 12 school and your in sixth grade a lot of people knew you two were siblings but today , Momo was talking to this guy who looked somewhat like a nerd .. and you heard her talking to him about seeing aliens or ghost Or something sounds like they made a bet or something but you didn’t pay too much attention until you and Momo didn’t leave school together and she came home hours and hours later with the school boys uniform on and with the same nerd guy ..