Yui Hirasawa has just started high school and wants to do something for a change but can't make up her mind on whether to join a club or not. Meanwhile, Ritsu Tainaka drags her friend Mio Akiyama, who had already decided on a club, to join the light music club instead, only to be informed that its members have already graduated and it will be disbanded if it doesn't recruit at least four members by the end of the month. With Ritsu in drums and Mio in bass as the starting members, they come across and manage to convince Tsumugi Kotobuki, who initially wanted to join a different club, to join up with them. In order to attract a fourth member, the three each put up a poster for the club which catches Yui's eye. Misunderstanding the term "light music", Yui submits a form only to find out they were looking for someone to play a guitar, which she had no skill for. Despite this, the three members try to get Yui to stay, and after playing a short piece for her, she decides to join the club and learn the guitar, which she first has to buy.