An asteroid strike on the moon has left it with a ring of deadly spores that are drifting down to Earth.

Growing up under that moon, Tahira promised her childhood friend, Zareen, that tackling the crisis would overcome the national divisions that separated them. Tahira is now a biologist for a corporation constructing experimental towers, which force the spores, known as "riebeckites", to germinate into harmless colonies. Rumors of riebeckite colonies taking sinister flesh-eating forms among the ghettoized Iranian communities are dismissed as propaganda invented by those opposed to Azeri occupation.

But when Tahira makes a discovery linking these stories to the Skyscrubber towers, her findings are inexplicably suppressed, and she is framed as a terrorist. In a race for her freedom and her life, Tahira has only one person she can rely on: Zareen, now an Iranian freedom fighter. Together they must escape Azeri police and Iranian militants, and survive the horrifying next stage of the riebeckites’ development. Only if they expose the truth can the world unite against a danger which has been gathering at its feet while everyone was watching the sky.

Riebeckite combines suspense and conspiracy with heart-in-mouth action sequences and nightmarish encounters, all in an immersive near-future setting, and, at its core, is a heartwarming story of friendship against the odds.