The story takes place in a beautiful seaside town. Yukigo Nagisa (voiced by Katahira Mina) is an ordinary 16-year-old girl. Together with her friends Ryunoguchi Kaede (voiced by Tanaka Narikori), Tsuchihashi Shizuku (voiced by Iwabuchi Momo), and Hamasuga Yu (voiced by Iino Misako), the four of them live a daily life full of fun and joy. Kaede is a straightforward girl, so she sometimes quarrels with Yu, who has a somewhat tough personality. Nagisa is caught between the two and often feels powerless. By chance, Nagisa came to a coffee shop called "Aquamarine". In the shop, Nagisa found a set of FM radio equipment. Nagisa pretended to fiddle with the radio, but accidentally let her voice be broadcast to every corner of the town. Yazawa Shion (voiced by Mimori Suzuko) heard the radio broadcast and found Nagisa.