Caliban's War recap

Eighteen months after Eros, a monstrous figure that survives hard vacuum unarmored destroys a Martian marine patrol on Ganymede, and the resulting battle wrecks the moon that feeds the outer planets. Gunnery Sergeant Bobbie Draper, the only survivor, is sent to Earth to testify and, when her account is suppressed, allies herself with UN official Chrisjen Avasarala, who is hunting whoever is still working with the protomolecule. On Ganymede, botanist Prax Meng searches for his young daughter Mei, taken by her doctor, and joins James Holden and the Rocinante when they arrive to investigate. The threads converge: the industrialist Jules-Pierre Mao, protected by figures inside the UN government, has been using children with immune disorders to grow protomolecule-human hybrids as weapons. Avasarala is lured aboard Mao's ship and effectively held prisoner until Bobbie fights their way out to the Rocinante. The crew track the program to Io, rescue Mei, destroy a hybrid, and stop a missile launch aimed at Earth. Mao and his backers fall; Avasarala rises. On Venus, the protomolecule finishes its work, leaves the planet, and builds an enormous ring beyond the orbit of Uranus.

Previously: an ice hauler was destroyed in the Belt to provoke a war, and the accusation broadcast by its surviving officer, James Holden, nearly set Earth, Mars and the Belt against one another. The real cause was a corporation, Protogen, testing an alien artifact recovered from Saturn's moon Phoebe. The protomolecule was deliberately released on Eros Station and killed its roughly one and a half million residents as an instrumented experiment. Holden and his crew, engineer Naomi Nagata, mechanic Amos Burton and pilot Alex Kamal, came through it with a captured Martian corvette, the Rocinante, and an alliance with Fred Johnson, the former UN colonel who leads the Outer Planets Alliance from Tycho Station. Ceres detective Miller, obsessed with a missing woman named Julie Mao, found her dead of the protomolecule on Eros and later found that her surviving mind was steering the infected station toward Earth. He rode the rock down into Venus with her and died there, stopping it. The war was averted and Protogen destroyed, but the protomolecule is now growing on the surface of Venus, out of anyone's reach and visibly changing, and no government can tell what it is doing. About eighteen months have passed. Earth and Mars remain armed and suspicious of each other, and the Belt is stronger and more organized than before.

On Ganymede, the agricultural moon that feeds the outer planets, Martian and United Nations garrisons watch each other across a demilitarized line. Gunnery Sergeant Bobbie Draper's Martian patrol is destroyed by a single humanoid figure that crosses open ground without a vacuum suit and tears through powered armor; she alone survives. The exchange of fire between the fleets above shatters the moon's mirror array and its growing domes, and Ganymede begins to starve. James Holden and the Rocinante are working for Fred Johnson in the Belt, hunting pirates, and Holden has grown harder and quicker to shoot than the man who once broadcast everything he knew. On Ganymede, the botanist Prax Meng learns that his four-year-old daughter Mei was collected from her daycare by her doctor hours before the fighting started, and that without treatment for her immune disorder she cannot last long. On Earth, the UN official Chrisjen Avasarala works the aftermath and concludes that the incident was engineered, and that the people who arranged it are inside her own government.

Bobbie is sent to Earth as part of a Martian delegation to explain the incident, and when her account of the unarmored figure is edited out of her testimony she understands that her own government would rather bury it than admit what is loose. Avasarala, who suspects the same thing from the other side, takes her in. Fred Johnson sends the Rocinante to Ganymede to look into the rumors, and Holden's crew find a moon collapsing into famine, refugees and gang control. Holden meets Prax, learns that Mei was taken by a doctor named Strickland, and begins to suspect that the missing children and the creature that killed Bobbie's platoon are the same story. Avasarala works out that the only private organization capable of continuing protomolecule research is one that already tried, and starts looking for who is sheltering it.

Following the trail of the missing children, Holden's crew and Prax break into a concealed laboratory beneath Ganymede's surface and find the remains of a program that selected children with compromised immune systems, Mei among them, as candidates for protomolecule work. Something is still alive down there; they meet one of the hybrid creatures and blow it out into vacuum rather than fight it. Prax joins the Rocinante's crew as they leave the dying moon. Avasarala, working through UN channels, becomes certain that the industrialist Jules-Pierre Mao is behind the research and that someone senior on Earth is protecting him, though she cannot yet prove which of her colleagues it is. Bobbie, cut loose by her own chain of command, stays on Earth as Avasarala's liaison and effectively her bodyguard.

Prax records a public appeal for help finding his daughter, and it spreads across the system, turning a private search into a cause with donated money behind it and giving the Rocinante the resources to keep hunting. The crew follow the program's supply lines outward from Ganymede. Avasarala, closing in on Mao, is maneuvered out of her own investigation: she is invited away from Earth on what looks like an opportunity and taken aboard Mao's private ship with Bobbie, where she finds her communications cut and herself a comfortable, well-fed prisoner while the people running the program proceed without her. Meanwhile, on Venus, the protomolecule is visibly reshaping the planet on an enormous scale, and every telescope in the system is pointed at it.

Avasarala learns aboard Mao's ship that her own superior, Sadavir Errinwright, is the man who has been shielding the program, trading UN cover for a weapon he believes Earth must have before Mars does. Admiral Nguyen, hawkish and impatient, commands the naval force protecting the operation. Bobbie takes matters into her own hands, steals a suit of powered armor, and fights the two of them off the ship in a stolen shuttle. They rendezvous with the Rocinante, and the crew, Prax, Bobbie and Avasarala are joined into one improvised alliance: an aging politician with no government behind her, a botanist looking for his daughter, and a corvette with no flag.

The program's location resolves to Io, a moon of Jupiter, where Mao's people have moved the laboratory and the children. Avasarala uses what leverage she still has to turn parts of the UN fleet against Nguyen while Errinwright works to save himself by cutting his patron loose. The Rocinante runs for Io ahead of the warships. Aboard the station there, the hybrids are being finished and loaded, and the researchers regard the children they consumed as materials. Prax, who has spent the whole voyage refusing to believe Mei is dead, prepares to go down with Amos to get her out, knowing the odds and going anyway.

The Rocinante reaches Io ahead of the warships and the crew go down to the laboratory buried under the ice. What they find confirms the worst reading of the evidence: the children taken from Ganymede were raw material, most of them are gone, and the researchers running the program regard the question of consent as a sentimental distraction. Doctor Paolo Cortazar, whose ability to form attachments was surgically removed years ago, explains the work cheerfully to anyone who asks. Elsewhere on the moon the finished hybrids are being loaded into missiles. Above them, Admiral Nguyen's warships hold position while Avasarala, aboard the Rocinante with no office and no title, works the fleets by radio and calls in every debt she has ever been owed, and Errinwright manoeuvres to survive by turning on the patron he protected. Prax, who has refused for the whole voyage to accept that Mei is dead, goes down with Amos to look for her.

On Io the crew reach the laboratory. Prax finds Mei alive and early enough in the process to be saved, and Amos gets her clear; Katoa and the children taken before her cannot be recovered. The researcher Paolo Cortazar, whose ability to care about anyone was surgically removed, is taken alive along with his data. Bobbie meets one of the hybrid creatures on the moon's surface in powered armor and destroys it. Nguyen's ship launches a swarm of missiles carrying hybrids at Earth, and Avasarala, the Rocinante and the fleets she has turned destroy them before they arrive. Nguyen is arrested, Jules-Pierre Mao is taken into custody, and Errinwright is exposed and removed, leaving Avasarala far more powerful than when she started. Prax and Mei are reunited. Then the protomolecule finishes with Venus: a vast structure lifts off the planet, crosses the system, and settles far beyond the orbit of Uranus, where it begins to assemble an enormous ring.

On Io, the crew reach Mao's laboratory. Prax finds Mei alive, still early enough in the process to be saved, and Amos gets her out; Katoa and the other children who went before her cannot be recovered. Bobbie fights one of the hybrid creatures on the moon's surface in powered armor and destroys it. Nguyen's ship launches a swarm of hybrid-carrying missiles at Earth, and the Rocinante and the gathered fleets, coordinated by Avasarala, destroy them before they reach the planet. Nguyen is broken and arrested, Jules-Pierre Mao is taken into custody, and Errinwright, exposed as the man inside the UN who armed the program, is removed and disgraced, leaving Avasarala with far more power than she had. Doctor Cortazar is captured alive and his research falls into UN hands, which is its own unfinished problem. Prax and Mei are reunited, Bobbie ends up with no service to return to and a place among Avasarala's people, and the Rocinante crew survive intact with Holden somewhat restored to himself. In the closing days, the protomolecule on Venus finishes whatever it has been building: a vast structure lifts off the planet, crosses the solar system, and comes to rest far beyond the orbit of Uranus, where it begins assembling an enormous ring.