Set before the events of Jim Henson's fantasy masterpiece The Dark Crystal, Age of Resistance' three Gelflings – Rian, Brea and Deet – who inspire a rebellion against the Skeksis when they discover a horrifying secret behind their power that threatens the world of Thra. The Skeksis are a reptilian bird-like race that ruled over Thra for nine hundred and ninety-nine and one trine after the end of the Age of Harmony. They were created when the Fallen urSkeks attempted to purify themselves through the heat of the three suns shining on the Crystal. Instead of being cleansed of their darker natures, each urSkek was split into two beings; the violent Skeksis and the peaceful urRu.