The King's Dagger - The Dragon Keepers, #1

Dragons Port is a bustling city of commerce and art that rests in the shadow of the Great Cliffs, home to the dragons and their riders. Also living in the Great Cliffs are the dragon keepers, men and women tasked with caring for and raising the hatchlings. Rick and Wren are two young dragon keepers in training whose primary concerns revolve around the hatchlings under their care. But when they get caught in an uprising in Dragons Port, Rick and Wren are separated from their own protectors.
Suddenly they find themselves on the run, having to rely on their limited training and inherent talents to outwit an enemy skilled in the art of hunting both dragons and dragon keepers. At the same time, the dragon riders must face a new threat from an old enemy. People are being killed, and so the dragon riders must fly to war before more innocents perish. Underlying it all looms a darker menace, one which everyone, even the dragons, have long since forgotten.
But the past will not stay hidden forever as the greatest threat to ever face both humans and dragons begins to awaken once again...