Physics rules us all, and physics means faster than light travel is impossible--until the discovery of the Flow. It is, more or less, an interdimensional field that can be accessed at certain points and make something that at least functions as faster than light travel possible. The Flow makes possible an interstellar empire, the Interdependency, whose ethos requires that each inhabited system be dependent on the others for some essentials.
It's a hedge against interstellar war.
It's a guarantee of power and control for the rules or the empire.
And now the Flow is proving to be less stable than long assumed. In fact, it's collapsing, and the empire can't survive.
We follow the increasingly alarming event from the viewpoints of three different people: Emperox Grayland II, the brand-new Emperox, who will also be the last Emperox; Marce Claremont, a Flow physicist who has been working on project secretly funded by the newly deceased Emperox, Grayland's father; and Lady Kiva Lagos, a profane, profit-driven businesswoman who discovers she has ethical feelings about intentionally leaving trillions of people to die when their access to essential supplies ends with the collapse of the Flow.
Every inhabited system will be cut off fron every other inhabited system.
It has already begun, and will be over in no more than a decade. That's how much time they have to find a way for humanity to survive the collapse.
This is told in Scalzi's typically fast-paced, funny, easy-reading style. It's a lot of fun.
And it's about the impending extinction of humanity, when no inhabited system, except possibly the exile system of End, will have the means to keep its inhabitants eating and breathing after the Flow collapses.
I love Scalzi's characters. They feel real and likable, with flaws and virtues and insights and blind spots. His storytelling is clean, and simple, and always more complex than it looks at first.
The Interdependency is a brilliant means of preventing interstellar war, by ensuring everyone knows they depend on everyone else. The Interdependency is a scam, created to enrich the ruling class and keep them permanently in power. Both things are true. The first is not made less true by the fact that the second thing was the founding purpose of the creation of the Interdepency and the Church of Interdependence. The collapse of the Flow will end the scam, but also quite possibly wipe out humanity.
And for all the light, fun feeling of the storytelling, it gradually becomes clear that Scalzi isn't going to give anyone any easy outs.
While several plot threads are brought to satisfying conclusions, there is a substantial cliffhanger here, and there will be at least one more book. I say buy it now, and don't wait to read it, but be aware that not everything is resolved in this book.
I bought this book.