The Hidden Kingdom (Wings of Fire #3)

The seven dragon tribes have been at war for generations, locked in an
endless battle over an ancient, lost treasure. A secret movement called
the Talons of Peace is determined to bring an end to the fighting, with
the help of a prophecy - a foretelling that calls for great sacrifice. Five dragonets are collected to fulfil the prophecy, raised in a
hidden cave and enlisted - against their will - to end the terrible
war. But not every dragonet wants a destiny. And when the select five
escape their underground captors to look for their original homes, what
has been unleashed on the dragon world may be far more than the
revolutionary planners intended…