"It's been 925 summers since the Jemen introduced zyme, a bioluminescent algae, into the world's ocean and unwittingly triggered an Ice Age that has consumed most of the planet. All but a handful of Jemen flew to the stars, but before they left, they recreated several extinct species that had thrived in the last Ice Age. After almost a thousand summers, the archaic hominins that struggle along the edges of massive glaciers are dwindling. All they...