The first in the series based on the popular PC game based on BISHOP Miyuki Todo, a teacher who works at the same school, and Eiji Sanada are lovers who are about to get married. Miyuki decides to protect her virginity until her marriage, but Takuya steals her virginity. Takuya also has relationships with Miyuki's colleagues Makoto and Ritsuko. He had a special ability to have a special semen that, when taken into his body, turned into a substance that produced breast milk. What will happen to Miyuki and Eiji's relationship, and what will happen with Takuya?