Dekiai no Ori

Tsukasa, the future successor to the Nikaidou Company, is a young and talented businessman. One day, during a party held in Monaco, he was drugged and kidnapped. Upon regaining consciousness, he was being auctioned off as a slave. Naked and bound, Tsukasa has taken the interest of many "buyers" whose identities were hidden behind masks. One particular buyer, the Earl, has bid the highest price and to Tsukasa's surprise, the Earl himself is none other the person who used to live in the Nikaidou household for ten years?

(Source: Oakla Shuppan, translated)