In the ninth book in the Ella and Owen series, the dragon twins are captured by grumpy goblins

When Squeaky the gremlin runs off with Owen's favorite book, the dragon twins follow him right into a goblin village. All Owen wants is his book back, but the goblin leader Grom the Terrible wants something else: to battle Owen.

Can Owen beat Grom the Terrible in a battle to win back his book and save Ella and Squeaky from the grumpy goblins?