Princess Bluerose is a small gnome living deep in the Norwegian mountains. A small community of gnomes is responsible for making the transition between daylight and night. This is the magic hour, created by the magic silver, of which only these gnomes possess. When the silver is stolen, the world is transformed into eternal night. Bluerose sets out on a remarkable journey to retrieve the silver and save the world from eternal darkness.

It's the harshest winter in memory, and the gnomes' very existence is in danger. Eager to help, Queen Fjellrose betrays one of their strictest rules and goes out looking for the Blue Horn, a magical instrument that can alter the weather.