The title refers to the radioactive rain that fell after the first atomic bomb was let off over Hiroshima. Although young bride-to-be Yasuko has the misfortune to be visiting the city in question on the day of the explosion, she is miraculously unhurt and returns to her village across the bay. Unfortunately, the whole region has been profoundly affected by the ?black rain? which over the following years is responsible for the poison that slowly but surely erodes their souls. Yoshiko's former friends insist that they can't be sick, that she must be the one to have brought this illness to them. Now a pariah, Yoshiko's life is shattered as surely as if the bomb had disintegrated her upon impact.