In the dusty Mars city of Cydonia, only one path is open to women: get married and breed. As long as you're genetically approved, of course. Eighteen-year-old Kayo Rooper might be approved, but she has no interest in finding a husband. Her destiny is to live a life of adventure on Earth, birthplace of her long lost mother.

Joined by a friend with a shady moral compass, a tech genius with a tragic past, and the roof-rat-turned Sentinel who both threatens and attracts her, Kayo earns passage money to Earth riding her Hellcat cycle as an illegal courier. But her plans of escape are threatened when a job puts her in the middle of a plot to destroy the fragile alliance between Earth and Mars. Now, the very home Kayo wants to escape is the one she would give anything to save.