It is time to tackle Tom’s mystery: locate his sister who went missing in the jungles of South America years ago. The Mystery Boys launch an expedition to investigate the mine where Tom’s father was killed and Margery was kidnapped by bandits.
They soon find a lead: an American miner on bad times promises to lead them to a man who knows more information about a girl with golden hair kidnapped years ago. However, the miner will not provide the name of the man until they arrive at the destination because he is afraid of being left behind.
Hurricanes, deadly animals and hostile tribes are just a few of the obstacles the group encounters. The Mystery Boys must be braver, smarter and more cunning than ever before to reunite Tom with his sister and make it out alive.


A wild adventure but it still seems more realistic than many Hardy Boys books. The boys don't manage to pull off this expedition without adults who have an idea what they are doing in the jungle. The dangers they face are ones you have heard of in these areas (whether true or not it is what audiences would thing existed). 

It is interesting in a series that is aimed at a younger reader to have a character who is in a lot of the book be an alcoholic. He's portrayed a little bit more complex than just a weak or evil man. There is some sympathy for his claim that can't control himself when he's near it. It is presented somewhat as a disease which usually was not the thought of the time