Teamed with his nephews Huey , Dewey , and Louie , and using the partial map from the library , Donald begins his search in Duckburg , with the trail being directed to an Aztec pyramid in Mexico . Outside the pyramid , he is directed by a " sweet seniorita " to obtain a " hero key " from an explorer back in Duckburg to open the pyramid . Inside the pyramid , Donald meets Goofy , who gives him a strange note and a plunger to help him reach higher places , and tells him that Gyro Gearloose is looking for him back in Duckburg . Travelling across the rooftops of Duckburg to meet Gyro , Donald is given Gyro 's latest invention , bubblegum ammo that can break through walls . The last location on the partial map is Count Dracula 's castle in Transylvania , where Donald encounters a ghost who tells him that the Count carries the real treasure map .