The protagonist, who has amnesia, does not know his identity, but he is able to live comfortable with the aid of his homeroom teacher Touko, and the rest of the school.
However, due to his lack of memories, he lacks dreams and hope, and felt an emptiness that makes him unable to attach to anything.
Then by chance, he learned what happened in the school, and decides to explore the incident that cost him his memory.
He sneaks into the staff room but is caught by Touko. To her, he reveals his emptiness over being an amnesiac.
Angry however, Touko rants over the pain of being a teacher for an amnesiac.
When the protagonist finds out about her true feelings, he driven by an addictive lust from his hear, and he then rapes her.
The taste of pleasure, and excitement since he lost his memories, and the joy of screwing a woman is what he's been missing.
Then, following his awakened desire, he decides to rape the other attractive female teachers just as mercilessly.