Tadala has lost everything: her village, her mother, her father, and now her adopted home. In the wake of his wife's death, her foster father Hakim has decided to leave everything behind them and trek deep into the desert. Tadala isn't optimistic about the life that waits for her at a small oasis, but it's the only option she has left. When a deadly sandstorm blows up and threatens their caravan, Tadala must make a split-second decision to save herself and Hakim's two young daughters: shelter with the rest of the travellers, or flee toward a mysterious smudge on the horizon. The mysterious smudge is a city, and in the city is a single person. Elabel is unlike anyone Tadala has ever met, and wields a bizarre power stronger than anything she could have imagined. But Elabel is facing other threats, and in her struggle to survive she pulls Tadala into a peculiar world of mechanical horses, floating cities, and threads.