The Iron Claw: The Warlock's Child Book Three

Not since Garth Nix and Sean Williams joined forces has there been such a great collaboration as Paul Collins and Sean McMullen!
The warlock Calbaras wants to revive the ancient, forbidden magic of dragons, and his son Dantar is vital to his plans. Dantar is on the run in an enemy kingdom, unaware that he is so important. Worse, his sister Velza is now working for the enemy king.