The Earth is dying. Darrow is a Red, a miner in the interior of Mars. His mission is to extract enough precious elements to one day tame the surface of the planet and allow humans to live on it. The Reds are humanity's last hope.

Or so it appears, until the day Darrow discovers it's all a lie. That Mars has been habitable - and inhabited - for generations, by a class of people calling themselves the Golds. A class of people who look down on Darrow and his fellows as slave labour, to be exploited and worked to death without a second thought.

Until the day that Darrow, with the help of a mysterious group of rebels, disguises himself as a Gold and infiltrates their command school, intent on taking down his oppressors from the inside. But the command school is a battlefield - and Darrow isn't the only student with an agenda.