I'm pondering a problem with my current WIP, and thought I'd throw this out there. In MG, and especially MG with a mysterious bent, we face a huge hurdle in creating a believable way for our protagonists to discover something, when all the grown-ups around them were unable to.

Some books solve this by making the adults ridiculous - which is fun. Lemony Snicket is very good at this. The kids are the only sane ones in most of his books. In his latest book, the MC's mentor is hilariously inept.

In my story, the protagonist wants to find something that a grown-up has been searching for his entire life. How can I make it believable that he finds it first? He's twelve. I was thinking that he could have some talent that the adult lacks. The thing is guarded by a secret sect of people, and one idea is to have the MC unwittingly befriend one of them. That's all I've got so far. I also played with the idea of him solving a riddle, but that is such a cliche.

Any advice?