Elementals: Ice Wolves (Book 1) by Amie Kaufman
Anders and his sister Rayna are twin orphans who live on the streets and pick pockets to survive. Their island, Vallen, is controlled by warring elemental creatures, Ice Wolves and Scorch Dragons, and their town is home to the wolves. When their thievery goes wrong at the famous Trial of the Staff, they both end up on stage and, remarkably, Rayna turns into a Scorch Dragon and Anders an Ice Wolf. This is meant to be impossible, since transformation powers are inherited and their family should be either dragon or wolf, not both.
Rayna is captured by dragons and flown to the mountains and Anders finds himself at the Ulfar Academy, where young wolves are trained. Anders is determined to find his sister again, believing she will be harmed by the dragons, and spends all his energies attempting to find her. But relations between dragon and wolf are bitter and his path is difficult and dangerous.
Amie Kaufman has seamlessly transitioned from her usual genre, sci-fi Young Adult, to produce an exciting middle-grade fantasy adventure set in a richly imagined world. Readers will enjoy the intrigue and the cliff-hanger ending will leave them breathlessly awaiting the next book. This is thrilling reading for fantasy and adventure lovers aged 10–13.