A great battle is on the horizon and drawing near. In preparation, Soren and his band must fly to the mysterious Northern Kingdoms to find allies and study the grim art of war.

Meanwhile, St. Aggie's has fallen to the Pure Ones. If they are not stopped, they will launch another, more deadly attack against the great tree. Without allies from the north, Ga'Hoole will surely fall.

Soren's mission must succeed. The final battle must be won. The coming conflagration will demand wisdom, bravery, and sacrifice from all the owls of the great tree, and from Soren and the band, nothing less than heroism.