Book excerpt: The latest in Kathryn Lasky's hit series - a stunning spin-off set among the wolves of Ga'hoole. A great cold has seized the Beyond. The warmth of summer, the smell of sweet grass and the great caribou migrations are distant memories. Now the wolves know only ice, dark, snow and endless cold. The order that kept the wolf clans strong for thousands of years has broken down completely. The wolves have only one chance for survival. They must find their way to a new land, a land of warmth and summer. But the journey will take them over a frozen sea and through thousands of miles of perilous territory. Will the wolves trust young Faolan to lead them?