Konatsu Amano must leave her familiar life in Tokyo and relocate to a small seaside town to live with her aunt when her dad gets a job abroad. This move brings about many challenges for the introverted girl, including starting at a new school and forming friendships with strangers. However, on her first day, she meets Koyuki, the only other member of the school's Aquarium Club, and is immediately drawn to her. As they spend time together, Konatsu and Koyuki, who are both lonely, realize they have a strong connection. But when another member of the club asks Koyuki why she initially approached Konatsu, her response is awkward and causes a rift between them. Will this tension break their bond?