Book excerpt: Praised as “one of the most inventive writers that science fiction has ever produced” (SF Site), national bestselling author Stephen Baxter presents a new saga of a world that could have become our own.... Ten thousand years ago, a vast and fertile plain existed that linked the British Isles to Europe. Home to a tribe of simple hunter-gatherers, Northland teems with nature’s bounty, but is also subject to its whims. Fourteen-year-old Ana calls Northland home, but her world is changing. The air is warming, the ice is melting, and the seas are rising. One day Ana meets a traveler from a far-distant city called Jericho—a town that is protected by a wall. And she starts to imagine the impossible....