Apocalyptic explosions, dead reactors, terrorists, mass murder, death-slugs, and now a blindness plague. This is a terrible planet. We should not have come here.

Cibola Burn, the forth book in the Expanse series, continues the story of humanity a few centuries in the future (when the solar system is conquered), where the first planet is explored / colonized following the stars gateway that is build by the alien protomolecule. The fast developments and lack of coordination between the 3 solar powers – Earth, Mars and Belters – make the exploration and colonization of the first planet available a chaotic process, where no one knows who owns the planet (first arrivals? or treaties signed in the Sol system?). How to impose law from years and light-years away?

In this chaotic environment, Holden and his crew is tasked to calm the tensions between the first arrived settlers and the Earth company that was given the rights to the planet. However, the planet is not what it’s looking like, it’s still a remnant of the alien empire that constructed the mysterious protomolecule, able to build a star gate a billion years later. And more puzzlingly, who was this other alien race that could destroy such an advanced and galaxy-wide spread empire?

This book in the series focuses on the planetary exploration, colonisation, survival and orbital manouvers, with a pinch of detective story to inquire over the alien ruins. It’s an engaging book, but felt slow at times. The sheer world-building, hard scifi, characters developments – remain world class.

The book is not as good as the previous 3 ones, where actions scenes, mind-blowing technology and memorable characters (Avasarala, anyone?) were introduced. All of the previous books were a ramp for the next volume of the series; however, after this volume, I am not sure where the story will go. However, I did like the cold calculation that the Earth politician is making over the ramifications for the powers of the Sol system of a star gateway opening. These were the gems of great writing and storytelling that made the book a good one, but not at the level of the others.

Overall, a great scifi series, book 4 / 9 read, and who know what future holds?