One Piece: Heart of Gold
A lady named Olga is pursued by both the World Government and a guy named Treasure, as she could be the one who knows the location of the Pure Gold, a substance that may get the world. Olga eventually ends sailing up with the Straw Hat Pirates, plus they journey to get the Pure Gold in Alchemi, which is located in the stomach of a huge angler fish named Bonbori's lost island.