On the Edge of the Dark Sea of Darkness By Andrew Peterson

The main character named Janner has longed to see the world and to know who his father is. But during the Dragon Day Festival he and his two siblings, Kalmar who likes to be called Tink, and Leeli are captured and thrown into jail by the fangs of Dang. But their mother Nia saves them by giving the Fangs jewels and promising them a maggot loaf then it becomes clear to the lead Fang that the Igiby family are possibly keeping the jewels of Anniera hidden in their house.