(W/A) Natsumi Ando Twin sisters Arisa and Tsubasa, separated by their parent''s divorce, are finally united after three years and Arisa asks Tsubasa to pretend to be her and spend a day in her school just for fun. At school everyone seems very nice to Tsubasa (who is pretending to be Arisa) and everything seemed normal -  until she finds a strange note in her sister''s shoe locker. After reading the letter, Arisa tries to kill herself. Tsubasa is determined to unravel the mystery behind the letter and her sister''s suicide attempt so Tsubasa continues to go to school as Arisa. Will she find out who sent the note and why it had such an effect on Arisa?