Story
The Unknown, a magical land teeming with blue fireflies, and Refugia, a highly-controlled city completely walled off from magic. One day inquisitive girls from Refugia discover a mysterious old book and a red necklace in a library. Without knowing what is in their possession, they curiously follow the blue fireflies out of the city, crossing barriers that no one has ever crossed before.
Synopsis via AniList (English).
