The Striga, former dragon owl from the Middle Kingdom beyond the Unnamed Sea, has come to stay at the great tree. He has earned the trust of all by saving Bell, Soren's owlet, from Nyra, and he grows daily closer to the young king Coryn, with whom he seems to share a strange bond. The Striga senses the power of the ember hidden in Bubo's forge and draws it closer. As his power waxes, he accuses the Band of treason and produces flimsy evidence to support his abominable claim. And so the Band is exiled, strengthening the Striga's hold over Coryn. The Band seeks refuge in distant forests and enlists the help of old friends, but every action they take is construed as further treason, and agents of the Striga - former Guardians - hunt them mercilessly, until for safety sake the band itself must separate. They devise as system of messages and alarms and so communicate despite their isolation. Old friends, loyal family and allies help devise a plan to shake the hold the Striga has on Coryn and to free the young king and the tree from this new, insidious tyranny. It will take courage, daring and wisdom, but the Band will meet the new challenge - for the sake of the king, and the Great Ga'Hoole Tree.

来自无名之海以外的中世纪王国的前龙猫头鹰斯特里加来到了大树下。他从尼拉手中拯救了索伦的猫头鹰贝尔，从而赢得了所有人的信任，他与年轻的国王科林的关系日益密切，他似乎与科林有一种奇怪的联系。斯特里加感觉到了藏在布博的锻造炉中的微光的力量，并将其拉近。随着他力量的增强，他指责乐队叛国，并拿出不可靠的证据来支持他可恶的说法。于是，乐队被流放，加强了斯特里加对科林的控制。乐队在遥远的森林中寻求庇护，并得到了老朋友的帮助，但他们的每一个行动都被认为是进一步的叛国，斯特里加的代理人--前守护者--无情地追捕他们，直到为了安全起见，乐队本身必须分离。他们设计了一套信息和警报系统，尽管与世隔绝，但仍能沟通。老朋友、忠诚的家人和盟友帮助制定了一个计划，以动摇斯特里加对科林的控制，并将年轻的国王和树从这个新的、阴险的暴政中解放出来。这需要勇气、胆量和智慧，但为了国王和伟大的嘎胡尔树，乐队将迎接新的挑战。