Due to the Libido Reduction Virus, humanity faced a serious population decline.

The government began developing a vaccine for libido reduction, targeting criminals. However, during clinical trials, a side effect was discovered where if the subject did not continuously release their excessive sexual urges, their DNA would break down, causing severe physical deformations. Despite the failed clinical trials, experiments continued on the test subjects, but one day, the lab was destroyed by an unidentified terrorist group, allowing the imprisoned test subjects to escape.

Yuri Hanasaki looks around in response to the people's screams. Mutant creatures were attacking civilians.

Remembering her father’s teachings to help the weak, she runs out to intervene...