Outcast by Michelle Paver

A thrilling story of friendship, survival, and the need to belong. For two moons Torak has hidden a terrible secret—and now it is revealed. He bears the mark of the Soul-Eater, and must pay the price. Cast out from the clans, he is alone and on the run: cut off from his best friend, Renn, and his beloved pack-brother, Wolf. He flees to the haunted reed-beds of Lake Axehead, where he is hunted by the Otter Clan, taunted by the Hidden People, and, as soul-sickness claims him, he falls prey to an even greater menace. Tormented by secrets and broken trust, he uncovers a deception that will turn his world upside down.