Harami Hime ~Reijou Ninshin Choukyou Keikaku~

Toru always looks for a chance to go into the upper-class society. One day, Toru gets a wind that ex-noble family, Kousaka, is up to his neck in debt. Toru offers Kousaka that Toru will help Kousaka finacially in exchange of Kousaka's daughters. But Kousaka refuses his offer. Toru confines his daughters during Kousaka's absence. He tries to make them pregnant and become the heir to Kousaka's family. Will he be able to get their bodies and hearts...? [From ErogeShop]