"Kanan and Tei live in a universe with carbon walls, small enough that fully grown humans can run around it in seventeen minutes. The earth under their blue-skinned feet is made of silica, and yellow suns glow out of a flat metallic sky. Whatever lies outside their universe is, by definition, Nothing. Just over their heads, in a place that shouldn't exist, lives an alien race. These creatures also call themselves human, but they have bodies without skin and tongues that speak gibberish. Their alien world is full of things Kanan and Tei are incapable of naming without betraying their own humanity. When a twist of fate brings these two worlds crashing together, Kanan and Tei find themselves racing unwillingly towards treason: Tei with his mind, Kanan with her legs. As their language grows, so does their universe. But the more they learn about the history of the human race, the more they wonder if they've ever truly been human--or if they even want to be."--Provided by publisher.