Milliken and Mae have never left the Trench--it's all they've ever known. They were born in The Trench, and they'll die there, just like all their people do. The two girls, eight and eleven, are a part of the Trenchfolk, a sprawling settlement of people living inside the massive ice walls of a vast, seemingly endless frozen trench carved into the surface of an otherwise icy wasteland. The Trenchfolk survive in this hostile world by following the Three Testaments of the Trench -- golden rules repeated like a mantra from birth to death... 1. The Trench provides, 2. You must never leave the Trench, 3. The Trench is endless.