Tensho School is located in Thrive Central's 7th Ward, where extracurricular activities are prioritized and all groups compete in a yearly fall singing contest. Saku Otonomiya, a transfer student, is struggling to adjust to his hectic new life after having to postpone the start of his school year owing to his older sister's hospitalization. He finds it tough to join a school group while juggling his part-time work and caring for his sister. The school's singing club wants to borrow Sousuke Kagura's song "Cloudy Days" in preparation for an upcoming singing competition, but Kagura is hesitant to give his permission. He feels that only a VOCALOID can sing the song because it demands a three-octave range.