Reincarnated into prison life, with a trash system

He wasn't the one the whimsical god wanted, so he was discarded to the side, with his memories locked up until the world was saved.
Who cares about that, though?
When his memories finally returned, he was standing in the courtroom, as the judge was sentencing him to a lifetime in prison for a crime he did not commit.
And although at first, the Prison Dungeon didn't seem so bad, he was about to learn that the prison, is not just a place...