The year is 2040. A young man named Reito, who suffers from a rare disease, undergoes cryosleep treatment after meeting his childhood sweetheart, Erisa. Five years later, when Reito wakes up, he finds that 99.9% of the world's men have been infected with a virus and died, and most of the 5 billion people in the world are women. This is the beginning of an erotic suspense story about the near future.