At the center of this mysterious story is a secret club full of intrigue. It all starts with the disappearance of an attractive young woman named Anna in one of the Japanese cities.

In the center of the plot is a small company that specializes in the development of erotic games. Most of the company's employees are young girls who have recently entered the industry.

After the sudden and mysterious death of his brother, Raika decides to enroll in his academy in order to understand the circumstances of his death and find out the truth. Since the school he attended is exclusively male, Raika is forced to pretend to be a guy.

This summer camp was supposed to be ordinary, but for Yuki, the manager of the baseball team, and her teammates, everything went wrong. They arrived on a private island for unusual training, but soon after their arrival, a civil war broke out there, and most of the men decided to leave the island to find out what had happened. Unfortunately, they never returned.

The main character, Urara-chan, finds a job at the women's academy. She leads a quiet and satisfying life and plans to get married soon. However, her fiance suddenly disappears, leaving behind significant debts.

Hentai's main character, Kaoru-kun, was an ordinary student in Japan. However, his life changed when his girlfriend Nanao humiliated him in public, forcing him to perform sexual acts. Anger and hatred boiled up in Kaoru, and every day his patience was wearing thin. Kaoru decides to take revenge on his abuser...

The young men unexpectedly invited their school friends into a small room. There they explained to the girls that they were now their "slaves." After that, the guys began to take turns forcing the girls into intimacy.

Hentai is a collection of three stories with different plots. The first one tells about the forbidden love between brother and sister. They face the problem of a closely related marriage.