Rinkai Gakuen

Seven years ago, Kurosawa Takashi, medical student and heir to a director of a hospital, attended a party for members of the high society. There he met young Takamine Rin, the daughter of a very wealthy family.
Knowing that she is far outside of his league, a dark desire awakened in Takashi: he must make her his thing.
However, his attempt to drug and have his way with her failed and he barely managed to escape the situation.

Fast forward to the present day: Takashi, unable to forget about Rin, attains a decent position in the underground society while managing to stay in Rin's vicinity.
He works as a personal doctor for her family and as a temporary doctor in her all-girls school.

Over the summer there is a school trip to a remote island planned. But that's only a diversion, the trip is actually organzied by Takashi's organization and its goal is to train some students into sex slaves.
There Takashi plans to make his move on Rin.