The Crucible of Pain (A Wolf in the Sun)

In the wake of war, only ash remains.

The Forgotten Ones are the humans who ruled the world before the beasts  took over. They have returned to conquer the land once more. After  enacting vengeance on the wolves of the Four Territories, they embark on  a long journey south where they hope to unearth the secrets of  uncontested dominance. Silversong can't let this happen. With his  companion Frostpaw, he leaves his pack behind to hunt down the leader of  the Forgotten Ones. Their pursuit takes them beyond the Northlands and  into a region ravaged by constant strife, and as Silversong trades blows  with the Forgotten Ones and recruits unexpected allies to the cause, he  becomes further and further entrenched on the bloody path to war.