Amos and Holden bring chicken as they accompany Prax to meet with the hacker. Holden observes how important finding Mei is to Prax and realizes he doesn’t love anything with that intensity, though he cares about Naomi, who is his lover. The young hacker asks for more food, and Amos, furious that he is holding information about a child hostage for chicken, beats him up. Prax explains that Mei and the other children treated by Strickland share a rare genetic disorder that disables their immune systems. Holden asks why Strickland knew to evacuate the kids just hours before the attack started; Holden suspects Strickland staged the attack to hide the abductions. Naomi maps the tunnels and finds a door where the security camera coverage ends. The crew decides to look there for Mei.

Naomi doesn’t like that Holden wants to go in with guns drawn. Prax explains the concept of the cascade, the way closed systems fail when one thing goes out of line and creates a domino-style collapse. If Ganymede Station fails, whole parts of the solar system will not have enough food to feed their kids. Prax wants to accompany the others to rescue Mei; he needs to be there when they find her. Amos gives him a gun. They travel the tunnels and run into a group of six guards who work for Pinkwater Security. Holden hires them. They reach the door.

Bobbie is bored by the diplomatic meeting and tries to guess which person in the room is the most important. Bobbie asks Thorsson why no one is talking about the humanoid creature that attacked them, and he says protocol has to be followed, as careers are at stake. Bobbi raises her hand. Avasarala calls on her, and Bobbie decides that Avasarala is the boss. Bobbie wants to talk about the monstrous creature, so Thorsson kicks her out of the meeting. She leaves the building for a walk, but finds Earth immediately overwhelming. A guard, another Marine, helps her. She tries to comprehend how some people can just live on basic support and be content not to work, but it’s too alien a mindset. Bobbie decides that all that matters to her is finding out who put the monster on Ganymede.

Holden leads the way through the new tunnels past the door. He reflects on Naomi’s warning that he is becoming the kind of person who shoots first, and wonders if killing people has changed him. They reach a workroom where there is a child’s body under the sheet. Prax recognizes the boy as Katoa. While Holden and Amos plan, Prax enters the next room and draws his gun. The room holds packing equipment and a dozen people, all armed. Holden is considering how to negotiate when Prax cocks his gun.

Prax thinks he is making a threat, not escalating, but Holden and the others react instantly, killing the armed guards in the room. The next room is a lab. After that, there is another room with more guards. Amos throws in a grenade, and Prax hears inhuman roaring. They enter the room and find complete carnage around a shattered cage-like glass cube.

At the sound of a ship launching, Prax panics that Mei is being taken offworld. There is more gunfire, and some of the Pinkwater guards are shot. Prax suddenly has a moment of intense empathy: “Everyone here was losing someone. His tragedy was just one among dozens. Hundreds. Thousands” (185). Prax inspects the glass case and sees “a network of fine black filament” (186). Holden tells Naomi they have to get off the moon right away.

Avasarala meets with the secretary general and Errinwright. Errinwright charges her with resolving the Venus situation, whatever that entails. Avasarala goes out to get a drink and runs into Bobbie at the bar. Avasarala decides to cultivate a contact who can keep her up to date on the Martian negotiations and invites Bobbie to work for her. Avasarala gets an update that James Holden joined up with Prax and was involved in a firefight. Avasarala orders that Holden be brought in.

Seeing the black filament puts Holden back in the nightmare that was the infected Eros Station, where human zombies were vomiting brown goo. Holden gives Wendell, the head of the Pinkwater team, the keys to their undercover ship, since Alex is coming with the Rocinante. Holden wonders how the protomolecule got on Ganymede. Fred Johnson of OPA has the only remaining sample, because Holden gave it to him. As they reach the ship, Holden is kidnapped and Amos is shot by mercenaries.

Bobbie meets with Thorsson and realizes he has nothing useful for her to do as part of the Martian delegation. Bobbie decides to work for Avasarala. She is curious when she sees Avasarala demeaning her assistant, Soren. She is even more curious when Avasarala gives Soren a memory stick with instructions to deliver it to Foster in data services, and Soren tosses the stick onto his desk. At 4 am, Avasarala summons Bobbie to her office to report that the situation around Ganymede has turned into a shooting war.

Prax and the crew of the Rocinante, as well as the surviving Pinkwater team, are detained. Amos is groggy from being shot with a nonlethal bullet. Medical staff work on an injured Pinkwater man. When their leg restraints are undone, Holden and Amos subdue the men holding them and escape. While the station is bombarded from above, the Rocinante crew and Prax make their way through the tunnels looking for a place to meet Alex. They put on suits and emerge onto the surface of the moon to see the Roci landing nearby.

Holden thinks of the Roci as home and safety. As the crew belt in for takeoff, Holden tells Prax to go to the crew deck and find a room. Holden shares that their new mission is to find Prax’s daughter; he’s certain “that this lost little girl was at the center of everything that had happened on Ganymede” (238). Alex notices an alarm in the cargo area but Holden instructs him to take off anyway. The flight out is dangerous as the Roci seems to be the new target for every ship that is shooting, but they make it past the blockade. Holden sets a course for Tycho Station, where the OPA is headquartered. He and Naomi have sex, then talk. Holden is convinced Fred is the reason the protomolecule is loose on Ganymede. Naomi says Holden is turning into someone she doesn’t know, and she wants off the ship.