River of Wind (Guardians of Ga'Hoole #13‪)‬

The adventure continues! In a land no owl knew existed, Soren, Coryn, and the Guardians find danger, knowledge, and new allies.Coryn and the Band have returned to the Great Ga'Hoole Tree and restored order. With the Ember safely hidden away, the tree shakes off its gaudy golden glow and recovers its natural majesty. Meanwhile, deep in the Palace of Mists, Bess finds an ancient map fragment that reveals that there are not 5 owl kingdoms -- as has been thought since time immemorial -- but 6. Coryn and the chaw of chaws set off to find this unknown land. In a landscape of perpetual winter, they discover a monastery of serene, learned owls, the likes of which no one has ever seen before.