28-year-old Manaka Mayu is a caregiver who works for ‘Himawari no Sato’, a facility for the elderly in Tokyo. She has been great friends with her grandmother Fumi since childhood, but has never met her grandfather, Toshiyuki, who was drafted as a crew member of the warship ‘Musashi’ shortly after marrying Fumi and died at war. Seeing her grandmother grow older year by year, Mayu feels a growing desire to learn what kind of person her grandfather was and also his last moments. Seeking clues, she sets off on a journey with Fumi and travels to Shikoku in search of Kiyama Mitsuo, a former crew member and a gunner in Toshiyuki’s squad on board the warship. They encounter a mysterious young man, Shinohara Toru, in Shikoku while looking for Kiyama. Although Kiyama had worked for the automobile factory that his nephew runs in his hometown of Oita Prefecture, he quit after his wife died of illness six years ago and goes on an annual pilgrimage of Shikoku. This is not only in memorial of his wife. There is a big motivation which he has never told anyone about. Kiyama has built an emotional wall and spent his remaining years quietly going on the pilgrimage. Then Toshiyuki’s wife and granddaughter show up. The facts that they are told by Kiyama is completely unexpected. The feelings of the four of them start to intersect now that the memories of 70 years earlier have been unlocked.
28歳の介護職員の真中麻有（石原さとみ）は、ある人物を探しに四国に旅に出た。麻有が探しているのは、武蔵の元乗組員の木山三男（津川雅彦）。実は、麻有の祖父・俊之は戦艦武蔵の元乗組員。その祖父がどのような最期を遂げたのかを知りたいと、年老いた祖母・ふみ（渡辺美佐子）とともに旅に出たのだ。お遍路に出ていた俊之の戦友、木山を何とか探し当てたふたり。そして、そこに現れた謎の若者、篠原徹（勝地涼）。木山から聞かされたのは、思いがけない事実だった。封印を解かれた70年前の記憶に、4人それぞれの思いが交差していく。
