Readers who made it through the first few unforgiving chapters of The Peripheral and went on to enjoy the rest of the book will find the beginning of Agency easier going, with the essential setup unchanged and many of the characters returning. In the main timeline sometime late in the twenty-second century, humanity has mostly overcome the interlocking crises that Gibson calls “the jackpot” and is now generally managing the planet without major additional damage. The price has been very high.
The central conceit of The Peripheral, Agency and the third part of the trilogy, which Gibson has said is simply called Jackpot, is that advanced computation has worked out ways to contact alternative pasts to the characters’ present, known in the book as “stubs.” Once contacted, the possibilities from that past branch off and lead to different futures, thus preserving causality at the future end. It’s all a bit handwavy, as it must be, but it works within the book because the limitations feel real, and Gibson keeps the rules consistent once he establishes them.
The Peripheral featured one stub, but implied the existence of many more. Gibson sets Agency in motion by having Detective Inspector Ainsley Lowbeer mention someone who had been a “hobbyist of hellholes.” (Ch. 2) Known as Vespasian, he apparently developed a method for intervening in stubs that led to dramatic changes away from the history known by the main timeline. Lowbeer has had him killed in the meantime, but she thinks she can adapt the method toward radically better outcomes than the main timeline. He had also made contact with a stub that was much further back than the others that Lowbeer and company had managed. The stub’s present is 2017, and its history saw the rejection of Brexit and the election of Hillary Clinton as US president in 2016. Unfortunately, as contact from the twenty-second century begins, the world is also in a crisis that threatens to escalate into nuclear war.