Protagonist and the younger sister Nozomi, brother and sister of difference by 4 years old. Very much in the friend in childhood, a calm, happy life was spent with parents. However, growing up Nozomi, protagonist comes to see younger sister as a woman.
And when Nozomi becomes in the third grade of junior high-school, a definite event wakes up. The first boyfriend in Nozomi was able to do, protagonist has let two separate from intense jealousy forcibly.
At this point Protagonist, no love as the elder brother, clearly love as a man is conscious. Brother and sister ditch deepens definitely by this, in addition parents divorced and the family scatters. Protagonist enters the university not in the local university but in Tokyo, it went out of local to run away.
And four years later. Protagonist that makes the university graduation nearby, it is rejoined by chance as Nozomi who has gone to Tokyo for the sake of the job-hunting. And the desire asleep in the Protagonist when speaking with her explodes. It made her drink sleeping medicine and confines she.