Cibola Burn recap

Refugees from Ganymede have squatted on Ilus, the first habitable world reached through the alien gates, and are mining lithium there when Royal Charter Energy arrives holding the United Nations charter for the same planet. Settlers blow up the landing pad, killing the company's governor and shuttle crew, and RCE's security chief Murtry answers with summary executions. James Holden is sent as a mediator, accompanied by an apparition of the dead detective Miller that only he can see and that wants access to the alien ruins. As the two sides escalate toward massacre, the planet itself wakes up: machinery buried for aeons activates, fusion reactors across the system shut down and leave the ships in orbit falling, a tsunami destroys the settlement, and an organism in the water blinds almost everyone. Biologist Elvi Okoye works out a treatment while the survivors shelter together in the ruins. Holden takes the Investigator into the alien network, shuts the planet down, and learns that whatever destroyed the builders is still out there and can reach through the gates. Murtry is arrested, settlers and company are forced to share the world, and the warning goes home with Holden.

Previously: an alien artifact called the protomolecule, released on Eros Station as a corporate experiment, killed more than a million people before the Ceres detective Miller rode the infected station into Venus to keep it from reaching Earth. The protomolecule kept working on Venus, and a later attempt by the industrialist Jules-Pierre Mao to grow protomolecule-human hybrids as weapons was broken on Io by James Holden and the crew of the Rocinante, the Martian marine Bobbie Draper, and the UN official Chrisjen Avasarala. The thing on Venus then lifted off the planet and assembled an enormous ring beyond the orbit of Uranus. When the fleets of Earth, Mars and the Outer Planets Alliance went to investigate it, they were trapped inside the space behind it by defences that had been waiting a very long time; thousands died before Holden reached the alien station at its centre and persuaded it to let them go. An apparition of Miller, an artifact of the protomolecule that only Holden can see, guided him there and has stayed with him since. The ring turned out to be one gate among more than thirteen hundred, each opening onto another star system with habitable worlds behind it. Governments have been arguing over how to control the rush ever since, and the argument has been overtaken by the people already going.

Refugees from the ruin of Ganymede crossed the gates without permission and settled on a habitable world they call Ilus, building a town and mining a rich lithium deposit to pay their way. Earth's answer is Royal Charter Energy, a company holding the United Nations charter for the same planet, arriving with a governor, a security force and a full science team aboard the ship Edward Israel. Told they are squatters on somebody else's property, a group of settlers led by Coop plant explosives on the landing pad, and the blast destroys the incoming shuttle and kills the governor and everyone aboard it. Basia Merton, who lost a son on Ganymede, helped set the charges and immediately regrets it. RCE's security chief, Adolphus Murtry, takes command of the company's response, identifies the men responsible and executes Coop on the spot. The company's biologist, Elvi Okoye, and its security officer Havelock find themselves on an expedition that has become a shooting war before any of the science has begun.

The United Nations sends James Holden and the Rocinante to mediate, on the reasoning that both sides distrust him about equally. Holden has no authority beyond his reputation and a warship in orbit, and neither the settlers nor Murtry intends to be governed by him. He also has a private reason for being there: the apparition of the dead detective Miller travels with him, visible to nobody else, and wants to reach the alien ruins scattered across the planet. Elvi begins cataloguing a biosphere built on chemistry that has nothing to do with Earth's, and finds that almost nothing on the world can eat a human being, which is not the same as the world being safe. Havelock, left aboard the Israel in orbit, watches his employer's position harden and begins recruiting and training the Belter contract workers on the ship into a security force of his own.

The standoff turns lethal. Murtry treats every settler as a combatant, and an exchange at one of the alien ruins leaves people dead on both sides and gives him the excuse to hunt the surviving conspirators. Holden's attempts to arrest and try people through any recognized process are ignored by everyone. Lucia Merton, the settlement's doctor, carries the knowledge of her own part in the bombing, and Basia goes deeper into a resistance he never wanted to join. Naomi goes up to orbit to help the settlers' aging ore ship, the Barbapiccola, which is barely spaceworthy and carries their entire fortune and Basia's daughter. Meanwhile the Investigator leads Holden to the buried machinery under the surface, and something down there begins to respond to being visited.

The planet stops being scenery. Alien structures that have been inert for aeons begin to switch on, one system at a time, without any interest in the humans standing on top of them. Slug-like organisms come out of the ground and kill people who touch them by discharging enormous current. The ruins hum. Elvi, trying to study a catastrophe as it happens, realizes the changes are neither random nor natural but the restart of a machine, and that the machine is the planet. Murtry treats the alien activity as another front in a war he intends to win, and Holden, who has seen what the protomolecule's works do when disturbed, cannot make him hear it. The Investigator becomes more insistent and less coherent, and Holden follows it because there is no one else who knows what any of it means.

The wake-up reaches its peak and the disasters arrive together. A burst from the alien systems shuts down every fusion reactor in the region, leaving the Edward Israel, the Barbapiccola and the Rocinante powerless in decaying orbits with everyone aboard them counting hours. On the ground, enormous structures rise out of the crust and the displacement throws a tsunami across the coast that destroys the settlement of First Landing, killing many and leaving the survivors, settlers and company personnel together, sheltering in the ruins with what they could carry. Naomi comes down with the evacuees and finds she can barely move or breathe in a gravity her body has never known. The war between the two groups becomes irrelevant overnight, though Murtry does not accept that.

Then people start going blind. A microorganism native to the world's water invades human eyes, and within days almost everyone on the surface is sightless, including Holden and most of the settlers, with the company's few remaining medical staff blind alongside them. Elvi, working with failing supplies and her own failing vision, identifies the organism and gambles on an existing drug to kill it. The camp in the ruins survives on rationed water and improvised care, with Basia and Amos hauling supplies and Lucia treating casualties. Murtry, still functional and still armed, uses the chaos to move against the settlers' leadership, and Havelock, ordered to help him, begins to understand exactly what he has been working for.

Elvi's treatment works, and sight starts to come back to the camp. In orbit the ships are still falling, with the Barbapiccola's crew and Felcia aboard and no reactor to lift them, and there are days rather than weeks left. Holden accepts the Investigator's demand and lets it take him down into the alien network beneath the surface, on the theory that the thing that turned the planet on is the only thing that can turn it off. Murtry, who now understands that Holden is the only person able to end the crisis and that ending it on Holden's terms costs the company everything, sets out after him with the last of his loyal security to make certain the machinery is never shut down by anyone but RCE.

Holden reaches the alien machinery and the Investigator does what it came to do. The planet's systems shut down, the reactors restart in time to save the ships in orbit, the ruins go quiet, and the blindness is cured. What the Investigator learns on the way is the larger news: the civilization that built the gates was not destroyed by war or disease but switched off, all at once, by something reaching in from outside their own network, and that something is still there and still capable of it. Murtry makes his final attempt on Holden's life at the alien site and is stopped and taken into custody to face trial for the killings he ordered, with Havelock at last refusing an order. Lucia answers for her part in the bombing and Basia for his. The settlers keep Ilus and their ore, the company keeps its charter and its scientists, and the two are forced into a shared and unhappy occupation of the world. Elvi and Fayez stay to keep studying it. Holden takes the warning home, to a solar system already pouring colony ships through a thousand gates.

Holden carries the Investigator into the alien machinery beneath the planet and lets it do what it came for. It shuts the world's systems down, and the effects reverse together: the fusion reactors restart in time to save the ships whose orbits were decaying, the ruins stop killing people, and Elvi's treatment clears the organism from the survivors' eyes. What the Investigator finds in the process is the important part. The civilization that built the gates was not destroyed by a war or a plague but by something that reached in from outside their network and switched them off, and that something is still capable of doing it. Holden brings the warning back with him. On the surface, Murtry makes a last attempt to kill Holden and secure the company's claim by force, and is stopped and taken into custody to be tried for the killings he ordered; Havelock, who has spent the book following orders he disliked, is the one who finally refuses. Lucia Merton faces the consequences of her part in the bombing, and Basia has to live with his. The settlers keep their town and their ore, the company keeps its charter and its scientists, and the two are forced into an uneasy shared occupation of the world. Elvi and Fayez stay on. The gates remain open, and the rush to settle a thousand new worlds continues, now with a warning attached that almost nobody wants to hear.