The problem? You want the young characters to hold center stage and fix the problem.
That means, as a corollary, that the adults have to be the problem, be irresponsible idiots, or be kept down -- somehow.
I have read a book in which the hero met his father for the first time since he was one, and then later in the book, the father was killed off because he was too good an authority figure.
The best approach I've seen was one where the responsible adults were forcibly removed, and when they returned, they were first, obviously in ignorance of what had happened, and second, depowered (as a logical consequence of what they had undergone) and so forced into the role of mentor rather than hero. (Mentors would work well, but you have to explain why this Wise Old Man is not leading by example; however old he is, if you send children into the fray, it's obviously desperate enough for you to enter it.)