Two children who got swapped at birth grow up to become engaged to each other. It's an arrangement neither of them like, at first.

Only young Olga knows where to find an invaluable substance called Pure Gold. The Straw Hats must help her reach it before her enemies do!

Seeking a rematch, the Foxy Pirates trick the Straw Hats into landing on an island. But it's all part of a larger scheme to destroy them!