Three years ago Haruki’s parents were killed in a car accident leaving Haruki with no one but himself. Luckly, Haruki was soon adopted into the Nagisa family, but Haruki has a dark past that none of them knows. As it turns out Haruki’s father was a highly skilled trainer within a prostitution ring called Under Eden. Before he died Haruki’s father introduced the young boy to the local establishment in the city called Paradise. With the intention to follow in his father footsteps, Haruki befriends the master of the establishment and also gets access to various drugs and other equipment to use as he see fit.
As Haruki begins to live with the Nagisa family he sets his eyes on the beautiful wife Sayoko who is now his stepmother. Sayoko owns a small tea shop located at the bottom floor of their three story house. Her husband works at a company and is often out of the house or on business trips. Sayoko also has a son named Takashi who goes in the same class as Haruki, the two of them are friends, but Takashi doesn’t know about Haruki’s perverted interests. As time goes Haruki sets up a long term plan were he spikes Sayoko’s tea daily with aphrodisiac drugs over the course of three years. Meanwhile he is also drugging Sayoko’s husband to become less interested in sex due to impotence.
Sayoko is not the only woman Haruki has set his eyes on. At his school works the strict but very attractive teacher Reiko Fuyuno who is also a close personal friend of Sayoko. Reiko is however more difficult to pursue, since she hasn´t been drugged like Sayoko. One day Haruki feigns illness to stay at home. Using his manipulating skills he turns Sayoko’s motherly feelings of him into desire. With a devilish young innocence, an unnatural large penis, drugs and other utensils and with the assistance of Under Eden, Haruki is starting out his career as the youngest sexual degeneration trainer in Under Eden history. But he must be careful; Reiko’s younger sister Ryoko who works for the police is investigating the Under Eden ring and could potentially ruin everything…