The Firstborn, the mysterious race of aliens best known as the builders of the iconic black monolith in 2001: A Space Odyssey, have inhabited the writing of science fiction master Arthur C. Clarke for decades. In the first two books of his acclaimed Time Odyssey series, Clarke and co-author Stephen Baxter imagined a near-future in which the Firstborn seek to stop the advance of human civilization by employing a technology indistinguishable from magic. That fate was narrowly averted, at an inconceivable price. But now, 27 years later, the Firstborn are back. This time, they have sent a "quantum bomb" speeding toward Earth, a device that human scientists can barely comprehend, let alone stop or destroy. But when shocking new insights emerge about the nature of the Firstborn and their plans, an unexpected ally appears from light-years away.