Earth is dying. Thousands of workers, who live in the vast caves beneath Mars, mine the precious elements that will make the planet habitable. They are Earth's only hope. Until the day Darrow learns that it's a lie. Mars has been habitable - and inhabited - for generations. Darrow disguises himself and infiltrates their society, intent on taking them down. But the surface is a battlefield - and Darrow isn't the only one with an agenda.