The Hero Took Everything From Me, so I Partied With the Hero’s Mother!

As a member of the hero's party Ceres, has set out to defeat the demon king. But one day, he was suddenly dismissed by the hero, and he had to leave the party. All alone, Ceres sought to find a domestic slave to take care of him. What he saw at the slave market was Shizuko, the hero's mother, being sold as a slave?!