In the autumn of 2007, Kitahara Haruki (voiced by Mizushima Daisuke) is an ordinary senior high school student studying at the Affiliated School of Minesho University. In order to put a perfect end to his high school life, Haruki joined the light music club. However, the dismal management made this already unknown club almost collapse, and Haruki's good wishes were about to be shattered. By chance, Haruki, who was playing the guitar alone, suddenly heard a beautiful song. Following this voice, a girl named Ogiso Setsuna (voiced by Yonezawa En) appeared in front of Haruki. Setsuna is an idol in the school. Later, Setsuna joined the light music club at Haruki's invitation. The next to join was Touma Kasa (voiced by Nagatame Hitomi), a girl who can play the piano well. Everyone knows that Kasa is rebellious and unruly, but even so, Haruki still enthusiastically invited Kasa to "join the group."