The protagonist, Aida Takanori, works as an office worker, living a modest but happy life with his only daughter, Miku.

One day, while attending school, Miku is confessed by a senior named Yuuki, who is extremely popular among the female students.
Lacking self-confidence, Miku tried to refuse the relationship, but Yuuki's enthusiasm persuaded her to accept.

Miku gave her virginity to the senior she admired and lived happily every day.
However, Yuuki had a side that Miku didn't know.
He has a secret life, where he sexually develops girls he likes and arranges them for other men.

"I want you to let another man sleep with you so you can save me."

...When Yuuki begged Miku, she couldn't refuse and gave her body to another man.

The first man was a middle-aged teacher and a sexual harasser.
The second was a delinquent senior with a huge penis.
She even gone so far as to hook up with homeless people hanging out in the park and male classmates...

Covered in the desires of these men and repeatedly impregnated with sex, Miku soon became addicted to pleasure.

[From Official website]