A rebellious teen Natsumi arrives from Tokyo to a small provincial island in search for the treasure, left by her deceased mother. She’s in shock to find out that Reiko – Her aunt, a local AMA-SAN (traditional japanese free diver), is her mother’s identical twin sister. Because of the yearslong conflict between the sisters, the aunt and the girl had never met or even heard about each other till now. The aunt is reluctant to welcome the girl, who brings her bitter past, and want to get rid of her. Natsumi has to find the way to resolve the old conflict and reunite the family to find underwater treasure left by her mother and save herself from the big trouble she is in. Japanese 90’s pop songs from the Aunt’s youth, will be the unexpected ally to bring the family together again.