Future Train: To you who don't know "that day".

The story centers around a three-generation family and the memories of Hiroshima between 1975 and 2025. Back in 1975, Hiroshima is slowly rebuilding itself after the atomic building. There, lives Ogaki Sachie, a mother who survived the postwar era and single-handedly raise her two daughters while operating a local coffee house. Half a century later, in present-day Hiroshima, Sachie's granddaughter, Kuramochi Yuki, is now an employee at a local TV station and is assigned to produce a special program. She decides to talk to grandmother who brings up the untold past of Hiroshima for the first time.