Tensho School is located in the 7th Ward of Thrive Central, where emphasis is put on extracurricular activities and all clubs participate in an annual fall singing contest. Having to delay the start of his school year due to his older sister's hospitalization, transfer student Saku Otonomiya finds himself struggling to adapt to his hectic new life. Balancing his part-time job and caring for his sister, he finds it difficult to make time to join a school club. In preparation for the upcoming singing contest, the school's singing club wishes to use Sousuke Kagura's song "Cloudy Days," but Kagura is reluctant to grant his permission. The song requires someone with a three-octave range to sing it and he believes that only a VOCALOID can meet the standards. He allows for the club to use his song on the condition that they can find someone who possesses that vocal range to properly sing it. While racking his brain over the composition of his next song, Kagura stumbles upon Otonomiya singing "Cloudy Days" perfectly. He invites Otonomiya to form a unit with him for the competition. At the same time, the singing club tries to goad him into joining so they can use Kagura's song. As the contest inches closer, Otonomiya must overcome his uncertainty and decide who to team up with. Private Tenshou Gakuen is the seventh of ten school districts circled within a 130-meter tall wall with restricted entry and egress aside from officials. The academy is fully autonomous by the government but to strive for independence, the school allows students to engage in club activities after school, which comes with a strangely unique system. Each club is ranked according to its overall accumulated points gathered from various club activities and school events. Points can also be received by winning at the school's periodic Tenshou Gakuen Singing Contest, where many students compete. The members in the clubs work hard to win the contest for their goal.