Aigan Reijou -Ingyaku no Contract-

I, Koji Inada, am a son of ITU (Inada Technical United), no.3 company in the industry.
Hibiki is a girl whose father owns a company that is no.1 in the industry.
Few years ago, I was dumped by Hibiki. Since then, I was always looking for a chance to bring out my revenge.

The chance has arrived suddenly.
The world economy has collapsed, and her father's company went into bankruptcy.
I now got a chance to humiliate Hibiki, with the aid of Himuro-sensei.

[From DLsite English]