Caliban's War

Caliban’s War is the second book in the Hugo-Award winning science fiction series The Expanse, written by co-authors Daniel Abraham and Ty Franck under the pseudonym James S. A. Corey. Events of Caliban’s War follow on events of the first book, Leviathan Wakes, which is set in a future where humans have built colonies across the solar system.

In Caliban’s War, a botanist, Prax, sets out to rescue his kidnapped daughter with the help of Captain Jim Holden and the crew of the spaceship Rocinante. They learn that Prax’s daughter is caught in an experiment using the alien protomolecule that Holden thinks he destroyed in the first book. Meanwhile, United Nations undersecretary Chrisjen Avasarala, who has been tracking strange events on Venus, hires Martian Marine Bobbie Draper and unites with the crew of the Rocinante to stop the power players trying to turn the protomolecule into a weapon. In the midst of fast-paced heroic action, with the future of humanity at stake, the novel explores the boundaries of knowledge, the consequences of human ambition and arrogance, and the importance of human connection in the face of threats to survival.

This guide is based on the Orbit paperback edition published in 2012.

Content Warning: The source material and this guide feature depictions of graphic violence, illness, cursing, the death of a child, and child endangerment.

Plot Summary

The novel opens on Ganymede, a moon of Jupiter where humans have built a colony. Four-year-old Mei Meng, who has an immune system disorder, is kidnapped from her preschool by her Dr. Strickland; she sees a terrifying and grotesque transformed human in a glass cage. Martian Marine Sergeant Bobbie Draper’s unit is patrolling the surface of Ganymede when a monstrous humanoid attacks them, killing her entire squad before self-destructing. James Holden and the crew of the Rocinante are called on by Fred Johnson, the leader of the Outer Planet Alliance, to check out the trouble on Ganymede. Mei’s father, Prax, a botanist working on Ganymede, searches for her as the colony on the moon begins to collapse. He learns that several children who have Mei’s condition have also disappeared.

Bobbie, as the sole survivor of the attack, is sent to Earth as part of a diplomatic effort to ease tensions between Mars and Earth. Chrisjen Avasarala, an undersecretary for the United Nations, the governing entity of Earth, hires Bobbie to work for her as a liaison. Other factions in the UN, including Admiral Nguyen, seem eager for war with Mars. Avasarala instructs her assistant, Soren, to spy on Nguyen. In the meantime, Holden and the crew of the Rocinante reach Ganymede, where Prax enlists their help. They recover video feed showing Mei’s kidnapping and follow the tunnels to a secret lab that is heavily guarded. During the ensuing fighting, a ship lifts off, and Prax is terrified that Mei is being taken off-world.

In the wake of the carnage, Holden spots signs of the protomolecule that he thinks he and his partner, Detective Jim Miller, destroyed. In first novel of the series, Holden and Miller destroyed Eros Station, where the humans had become infected with the alien protomolecule, by crashing it into the planet Venus, at the cost of Miller’s life. Ever since, Venus has been behaving strangely. Avasarala is tracking reports about Venus, but no one understands what is happening.

Avasarala orders for Holden to be brought to Earth, but Holden and his crew evade capture. They fly away from Ganymede in the Rocinante, headed toward Tycho Station, where Holden wants to find out if Fred Johnson is responsible for letting the protomolecule loose. On Earth, Avasarala confronts entrepreneur Jules-Pierre Mao, whose company was responsible for the failed experiments on Eros, to ask him whether he is at fault. Mao denies being involved. However, when Bobbie discovers that Soren is giving information to Nguyen’s men, and that Nguyen has taken a fleet of warships to Ganymede, Avasarala realizes she’s been kept in the dark: Errinwright, the second in command at the UN, has been plotting with Nguyen. Her hunch is confirmed when Errinwright says he’s sending Avasarala on a diplomatic mission to Ganymede, to be escorted on Mao’s ship—a way to sideline her. Avasarala brings Bobbie with her and begins plotting her counter strategy.

On the Rocinante, the crew discovers that one of the transformed human-alien hybrids from the Ganymede lab has stowed away on their ship. He was infected with an evolving version of the protomolecule to become immensely strong, but also uncontrollable. The crew work together, with Prax, to dump the monster into space. When Holden confronts Johnson on Tycho Station, Johnson fires Holden for impertinence. Holden decides that the Rocinante will set out to find Prax’s daughter. Prax believes she is being held on Io, another moon of Jupiter.

Avasarala learns that Nguyen has dispatched ships to follow and kill Holden. She has Bobbie hijack Mao’s ship, and they meet up with and board the Rocinante. When they compare the creature that attacked Bobbie’s squad to the stowaway on Holden’s ship, they conclude that Errinwright and Nguyen are trying to create some kind of supersoldier. They employed Strickland to kidnap Mei and the other immuno-compromised children to experiment on them.

When Nguyen’s ships gain on the Rocinante, Bobbie suggests enlisting the help of the Martian fleet. With the help of Martian warships and Bobbie’s skills as a gunner, the Rocinante defeats the UN ships and heads to Io. There, more UN ships gather, some of them commanded by Admiral Nguyen and some by Admiral Souther, who is working with Avasarala to stop release of the protomolecule. Nguyen refuses to surrender, and his forces on Io release a barrage of alien-human hybrids into space. One crashes into Nguyen’s ship, infecting all on board. Nguyen refuses to surrender the codes that would let them track and destroy the other hybrids, so Holden boards Nguyen’s ship to confront him. With the help of another UN soldier, Holden retrieves the codes. Nguyen and his ship are destroyed.

In the meantime, Bobbie, Prax, and Amos land on Io. Prax and Amos enter a lab to look for Mei, while Bobbie stays outside to fight another hybrid creature. Much to her surprise, she defeats it. Inside the lab, Prax and Amos retrieve the children who are still alive, and Prax reunites with his daughter. Amos kills Strickland, and they all escape.

War is averted, and the protomolecule is contained for the moment. Avasarala is promoted, and Holden looks forward to being self-employed. But as the protagonists gather for a celebratory dinner, they see footage that an enormous structure has launched from Venus into the solar system: the next step in the protomolecule’s evolution. This event leads into the next book in the series, Abaddon’s Gate.