Kaisei Sakamoto is a 16 year old boy who is inclined to settle everything with his fists. He grew up in a town where you can see both Nagazaki and Gunkanjima, living with his father. His father, Genkai Sakamoto, runs a small ramen shop. The father-son duo has just recently had a large fight. The story showcases fragments of one's youth and the questions that crop up while growing up.
Three stories from Shiratsuna Island: "Mikan no hana"
Shiratsuna Island is the only remaining island city in Japan, but it is being merged with a city on the opposite shore. Housewife Misato Tomita lives on the island. "Umi no hoshi"
Yōhei Hamasaki, who was born on Shiratsuna Island, lives in an apartment in the outskirts of Tokyo with his wife, Tomomi, and their son, Taichi. "Kumo no ito"
Popular artist Hirotaka Kurosaki, who is a native of Shiratsuna Island, goes back to his hometown after seven years.