Gyakkyou Burai Kaiji: Hakairoku Hen (Kaiji: Against All Rules)
After the events at the Starside Hotel, Kaiji Itou finds himself living his miserable lifestyle once again. Captured by the Teiai group to which he owns a lot of money, he is thrown into an underground forced labor camp where he must pay off his debt by doing harsh manual work. Kaiji becomes desperate as it is expected that he lives in this hellhole for the next 15 years.
[Source: Anime News Network]