Orphan Sickly

Benjirou was offered a job at the school with Orphans. His sister is attending her first year. Benjirou, is asked to clean out the science fall after school. After completing his work he falls asleep. He sees a girl gyrant him in his dreams. Who is she? He know her from somewhere, but he can't remember her. Outside he finds an android's head outside. Read on, please.