For eons, Earth has been under observation by the Firstborn, beings almost as old as the universe itself. The Firstborn are unknown to humankind — until they act. In an instant, Earth is carved up and reassembled like a huge jigsaw puzzle. Suddenly the planet and every living thing on it no longer exist in a single timeline. Instead, the world becomes a patchwork of eras, from prehistory to 2037, each with its own indigenous inhabitants.

Scattered across the planet are floating silver orbs impervious to all weapons and impossible to communicate with. Are these technologically advanced devices responsible for creating and sustaining the rifts in time? Are they cameras through which inscrutable alien eyes are watching? Or are they something stranger and more terrifying still?

The answer may lie in the ancient city of Babylon, where two groups of refugees from 2037 — three cosmonauts returning to Earth from the International Space Station, and three United Nations...