When her dad gets a job overseas, Konatsu Amano has to leave the Tokyo life she's always known and relocate to a small seaside town to stay with her aunt. The move also means starting a new school surrounded by complete strangers, and it's a lot to handle for a girl who has trouble with change. But on her first day in her new town, Konatsu is instantly drawn to Koyuki, an older girl who is the sole member of the Aquarium Club. Konatsu's introverted tendencies are hard for her to overcome, but maybe she's found something worth coming out of her shell for?

Konatsu is doing her best to adapt to her new school, but being required to join a club has introduced additional pressures. Her friendly classmate Kaede invites her to join the Home Ec Club, but Konatsu hasn't even had time to consider which club she's interested in. Meanwhile, Koyuki is like a ray of sunshine in Konatsu's cloudy world. Will Konatsu join the Aquarium Club?