In 1949, two years after the tumultuous events of Godzilla Minus One, the Shikishima family face an all-new calamity.

Following the death of the unmarried and childless Taki, Takeshi, a young relative of hers, discovers several pages of closely written lines in which the old lady has recorded her memories. This is how he learns the truth about her youth working as a housemaid and nanny for the Hirai family in a little house in Tokyo with a red gabled roof.