Kengi Hakunetsu: Law Zoro Tsui ni Kenzan!

Inside the underground mines, Luffy and Bartolomeo are attacked by the Rail Car Man Avelon. Desire is attacked as well, which shocks her, as Bill had rescued her crew after it was destroyed. The three are then sent plummeting further underground, where they discover members of the Silver Pirate Alliance who are enslaved as miners due to not pleasing Bill. Bartolomeo manages to free his hands, and Avelon returns, unwittingly freeing Luffy from his silver ball with an attack. Luffy and Bartolomeo then work together to defeat Avelon, and upon hearing about this, Bill orders the underground mine to be buried.