Golden Son - Red Rising Saga-Book 2 by Pierce Brown
As a Red, Darrow grew up working the mines deep beneath the surface of Mars, enduring backbreaking labor while dreaming of the better future he was building for his descendants. But the Society he faithfully served was built on lies. Darrow’s kind have been betrayed and denied by their elitist masters, the Golds—and their only path to liberation is revolution. And so Darrow sacrifices himself in the name of the greater good for which Eo, his true love and inspiration, laid down her own life. He becomes a Gold, infiltrating their privileged realm so that he can destroy it from within.