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?

The day of the Aquarium Club's open house has finally arrived, and the shark show is a great success. Koyuki is so thrilled by the victory that she actually jumps for joy. But baring her feelings in front of everyone is too much for her to handle, and she ends up running away. Thankfully Koyuki's family and Konatsu accept her just the way she is. And as Koyuki and Konatsu spend more time together, each of the girls finds a place in her heart for the other.