The Search for Sunken Treasure is the 25th book in the series.
Geronimo goes off to the Ratlapagos Islands with his family in search of a long-lost buried treasure.
Holey cheese, what an adventure! I was off to the Ratlapagos Islands with my family in search of a long-lost buried treasure. But oh, how I hate traveling! Being on a ship in the middle of the sea wasn't my idea of a fabumouse time. And I was beginning to suspect that we weren't the only ones searching for the treasure...