100 years before the start of Avatar: The Last Airbender and as the world gears up for a potential threat from the Fire Nation, firebender Eithne and earthbender Anju are street urchins squatting in an abandoned structure in Ba Sing Se. In her dreams, Eithne frequents The Veil - an overlap between the spirit world and her own - where the mysterious spirit Sol has been teaching her a dark and powerful new type of bending.