이번에 제로니모는 브라질의 한가운데로 여행을 떠나게 된다. 제로니모의 절친한 친구이자 조언자, 본 볼트 박사가 그에게 도움을 요청한 것이다. 마을에서 루비에 대한 이야기를 듣고서, 이 루비의 진실을 밝히기 위해 떠나는 제로니모 탐험대와 루비를 노리는 악당들의 한판 승부가 펼쳐지게 된다.
Monkeyfur is a beautiful rat who live in the village. They are not like everyone who live in city. They live along nature. They have a big ruby and a lot of oil! They can be rich and live comfortable longly, but they liked their life and didn't want to sell the treasure for their nature. Monkeyfur could control monkey and snake to protect them, so she could protect ruby from the bad ones away.
Geronimo, who always want to be good didn't stole the ruby for them. Yes, it is really important to live with nature. We are trying to attack the nature and make it our things, but it is everything's nature. So, Geronimo taught everyone we should protect the nature for our life.