Silverwing

Shade, a young silverwing bat, is the runt of his colony. Determined to show how brave he is, Shade breaks one of the ancient rules that governs the bats. As punishment, owls burn the bats' roost, forcing them to migrate earlier than normal. While on the trip south to the Hibernaculum, Shade becomes separated from his flock during a rain storm. His destination is millions of wing beats away. Now he must find a way to make the journey on his own.

Shade, a young silverwing bat, is searching the countryside for his father when he discovers a huge glass building. When he flies inside, he finds a forest haven where, safe from predatory owls, hundreds of bats are finally living in the sunlight. But when he tries to find an exit, Shade quickly realizes that instead of a paradise, the building is really a prison.