Miyata Ayaka, an office worker, sees her world collapse around her when her mother Miyata Harumi collapses due to illness and is left in a coma because of it. She then discovers that her mother kept a secret diary that she writes with her high school friends and that the lies she has told her have become evident, with nothing to lose. Ayaka will travel to Kaga, in Ishikawa Prefecture, her mother's hometown, to try to clarify the truth of the lie in her mother's secret diary.