Silver Mine Arc

Counted twelfth among the anime's filler stories, and third of those to air once the timeskip was over, this arc was built to usher in the feature One Piece Film: Gold. Its stage is the abandoned island of Silver Mine, ruled by the Silver Pirate Alliance. The plot cuts Luffy off with Bartolomeo, captain of the Barto Club, setting the pair against the alliance's leader Bill and closing the loop back to the movie's antagonist, the casino magnate Gild Tesoro.

Baited by a flying slab of meat, Luffy and Bartolomeo are hauled off by the abductors Desire and Peseta and delivered to Silver Mine. Once inside, Bartolomeo is put to work digging ore while Luffy is trapped within an enormous silver sphere. Bill, who shapes weapons out of his ore-devouring Devil Fruit, moves to kill Luffy, but Bartolomeo tears loose and the pair flee together. Bill then looses the wheel-limbed Aveyron to run them down through the tunnels, and it comes out that Bill has also marked Desire for death.

Luffy bursts his silver shell, beats Aveyron with the man's own cannonballs, and the three rally the enslaved miners into a breakout. Zoro turns up to send Peseta flying, and Law warps Kin'emon in to slice through molten ore, opening a path to the surface. Desire lingers to settle with Bill, who admits he slaughtered her original crew himself so he could win her trust with a staged rescue. Luffy batters him, and Bill gorges on ore to balloon into a colossal shape, flooding the doomed island with lava. Bartolomeo flings the molten ore back to sheathe Bill in silver, and a Grizzly Magnum from Luffy hurls him into his own fortress.

With the island going under, the Straw Hats, the Barto Club, and the liberated Silver Pirate Alliance clear out together. Desire turns down Bartolomeo's invitation to join the Barto Club, opting instead to pursue her own goal of climbing to the summit, and her Sweet Pirates leave on good terms. That evening the servant Tanaka reports back to Gran Tesoro that Bill sank along with Silver Mine, but Gild Tesoro is unbothered, noting that the true entertainment is only about to start, which leads straight into Film: Gold.