A historical novel that casts the Imperial Library as a protagonist, intertwining the memories of a woman named Kiwako with those of a would-be writer who visits the former Imperial Library in Ueno. It traces how books and people are reconnected through the library's journey from the Meiji era to the postwar years.

If a library had a heart, what history would it carry? The story quietly layers the fate of the Imperial Library over Kiwako's memories.