Reito Mizuhara goes into cryostasis to wait out a cure for a degenerative illness. He wakes five years later to a world ravaged by the MK virus, a pathogen that killed 99.9 percent of the male population while leaving women untouched. Reito turns out to be one of five men in Japan found immune, and the women now running society expect him to enter a state breeding program to help rebuild the human race.