Summer holidays... Amano Aki follows her mother, Haruko, to her hometown in Kitasanriku. There, she meets her maternal grandmother, Natsu, for the first time. Natsu is a woman diver, and Aki thinks that is just so cool. Aki is a second year high-school student, and she struggles to keep up with the fast-paced life in Tokyo. Having been confined indoors most of the time, everything she sees in the rural town is exciting to her. But most of all, seeing her grandmother diving under the fierce surf along the coastline, leaves a huge impact on her. "I think I would like to be a diver too..."