Manaka Mukaydo and Hikari Sakishima - childhood friends. She is- Unsure of anything crybaby. He - a great friend and comrade, who always help and comfort her best friend. These two and a couple more of their friends live in the sea, and the school have also been under water... until it closed. What to do,if the only school in town closed their underwater? Correctly! It is necessary to enter the ordinary "earth" school, the benefit to the land they live too.