Una Tomba Per Le Lucciole by Akiyuki Nosaka

After wartime firebombing destroys their home and family, teenage Seita and his young sister Setsuko struggle to survive alone, facing hunger, illness, and the indifference of those around them. The siblings' tender bond and small moments of joy — symbolized by the fireflies they collect — stand in stark contrast to the relentless deprivation and social breakdown that leads to heartbreaking loss. The novella is an unflinching portrait of the civilian cost of war and the fragility of human dignity in its aftermath.