Nagisa Yamada is a junior high school student who lives in the remote countryside town of Tottori. Her father has passed away years ago, and her mother does part-time jobs to support the family. She is a realist, and wants to graduate as soon as possible to live her own life. Mokuzu Umino is a melancholic and very mysterious transfer student. She claims to be a mermaid, come to land on a mission to find a true friend before the storm comes. At Tottori, the two girls meet, develop a unique friendship, and do what they can to keep living.