不老不死のお薬だしときますね

The opening of a journey to deliver the medicine of immortality——!? Yaosaka, a highly skilled Elixirist, is sold as collateral for a debt by his partner of seven years, the beautiful Gambler Hafutei. Yaosaka ends up living as a slave at a certain Duke's mansion. However, thinking there might be a reason for the betrayal by the woman he traveled with for many years, he decides to escape from the mansion to help her as his partner. While leading a surprisingly comfortable slave life and steadily advancing his escape plan, it seems the young lady living in the mansion has some kind of secret——. Will Yaosaka be able to reunite with his partner Hafutei!? And where will the journey to deliver the Elixir of immortality lead——!!