At the edge of the Arctic, in the first shivers of the polar winter, Rob, an eccentric scientist, leads Sébastien, a young musician, on a quest to hear a forgotten song: that of the Northern Lights. This meeting gives birth to a common dream, to transform this celestial song into music. However, while traversing the peaks inhabited by these ghost dancers, the two men find themselves confronted with human pollution, gradually nibbling away at the last free spaces in the world. Blending the scientific approach with a treasure hunt, Rob introduces Sébastien to the beauty of an endangered world, and questions the importance of safeguarding poetry and dreams in a fairytale between sky and earth.