Kana, a high school student, has her first boyfriend. Kazuki-kun is the one she has always admired. So she doesn't want to fail her first time. She doesn't want to be seen as bad at it. So Kana uses her filthy, smelly grandfather, who she cares for at home, as a practice subject for sexual intercourse. Her first kiss, hand job, blowjob, and sex were all with her grandpa. And it was all for Kazuki-kun...