The first book in a gripping duology introduces a fractured world on the brink of either enlightenment or war. Raisa of Upper Earth has only lived a life of privilege and acquiescence. Ever dutiful, she accepts her father's arrangement of her marriage to Lein, Crown Prince of the corrupt, volatile lands of Lower Earth. Though Lein is a stranger, Raisa knows the wedding will unite their vastly different worlds in a pact of peace: an infusion of Upper Earth technology will usher in the final age of enlightenment, ending war between humans forever. Or is justice more urgent? Newly released from imprisonment, Nada of Lower Earth has found her own calling: disrupting the royal wedding. Convinced her cousin Lein's alliance with Upper Earth will launch an invasive, terrifying form of tyranny, Nada sets out undercover to light the spark of revolution. When Raisa goes missing a week before the wedding, all eyes turn to the rebels, including Nayf, Nada's twin brother, a fugitive on the run. In Nayf and Raisa meeting, the long-simmering animosity between their worlds slowly burns away into something unexpected. But the Crown Prince wants his bride -- and future -- back. And he will go to the ends of the earths to reclaim them.