In seventeen-year-old Jax Mitchell's world, humans are nearly extinct and alien settlers have arrived. Until recently, the E'rikon have remained segregated in their city and ignored the few humans who have tried to engage them… but now they have taken Jax's brother. To rescue him, she forms an uneasy alliance with a teenage E'rikon left stranded in the woods. She agrees to guide him to the city if he sneaks her past the human-proof barrier. Too bad it's not that simple.