Cubs Stellan and Jytte survived their treacherous trek across the Nunquivik, but their quest to rescue their mother has only begun. Svenna is imprisoned at the sinister Ice Clock--the headquarters of the Gran Patek, whose dangerous influence is spreading throughout the bear kingdom. Only one bear has ever stood up to the Grand Patek--Svern, the cubs' father, a famous warrior who's been in exile for years. And so, along with their friend, Third, the cubs set out to find Svern in the legendary Den of Forever Frost--a place some bears claim never existed at all. But time is running out. The Grand Patek has a secret weapon at his disposal--one with the power to destroy everything the creatures of Ga'Hoole hold dear.