Sigrid is an 18-year-old elf who has kept a dangerous secret for years—an ability to use the raw energy of the crystals her community is enslaved to mine for the brutal yfir-búar, or “toplanders.” When the toplanders attack her mine and torture her father, Sigrid’s adherence to the elves’ culture of non-violence vanishes as she unleashes her power against the intruders. Fearing further retribution against all elves, Sigrid ventures through the forbidden “toplander door” to stop them. There, she finds marvels beyond any story her elders ever told.