Martha Wells’s Platform Decay (2026) is the eighth installment and third full-length novel in the critically acclaimed science fiction series, The Murderbot Diaries. A blend of space opera and cyberpunk, the story continues the adventures of Murderbot, a security android that has hacked its own governor module to achieve autonomy. The series has received numerous Hugo, Nebula, and Locus Awards, and has been adapted for television by Apple TV+.

The novel builds on the series’ established universe to explore themes such as The Continuous Struggle for Autonomy and Personhood, The Importance of Trust in Found Family, and The Illusion of Safety in a Controlled World. Wells, whose background includes a degree in anthropology, uses Murderbot’s darkly humorous first-person narration to subvert genre tropes, presenting a powerful artificial intelligence defined by empathy, anxiety, and a protective instinct toward its chosen humans. Its ongoing journey of self-discovery is set against a backdrop of unchecked corporate power and systemic violence, providing a critical perspective on a potential future dominated by capital.

This guide refers to the 2026 Tor Publishing Group edition.

Content Warning: The source text and guide feature depictions of graphic violence, mental illness, death, and cursing.

Plot Summary

The eighth installment of the Murderbot Diaries series follows Murderbot, a self-aware security robot (SecUnit), on a dangerous extraction mission inside a massive planetary torus. Murderbot narrates in first person, punctuated by emotion checks from a recently installed mental health module suggested by its therapist, Dr. Bharadwaj. In the previous novel, Murderbot and his Preservation team joined forces with a sentient ship named ART to save its team and hundreds of colonists from a planet overtaken by alien contamination. After successfully completing its mission, Murderbot decides to join forces with ART, even as it finally recognizes that its home and family are with Dr. Mensah on Preservation Station.

The story opens with Murderbot and Three, a younger and recently freed SecUnit, approaching a space dock controlled by Barish-Estranza (B-E), a powerful corporation. Murderbot is not physically present; a partial download of itself is riding Three’s hardware. Three enters the dock and triggers chaos as a distraction while Murderbot cuts the security cameras. Meanwhile, Murderbot’s actual body awakens inside a sealed cargo case in a separate bay, hidden by a stealth field.

Disguised as a civilian, Murderbot infiltrates the torus interior. The torus’s feed, a shared data network for communication and system control, is localized to individual zones, complicating its mission, as it must cross several zones. Murderbot boards a ground vehicle to reach a B-E installation.

After hacking the installation’s security, Murderbot finds a house with no feed connections, designed for people who need to remain hidden. Inside are three family members of Murderbot’s closest friend, Dr. Mensah’s: Farai, one of Mensah’s two marital partners; Naja, an older woman called “Nanna” by the family; and Sofi, Mensah’s daughter. Also present is Supervisor Leonide, a B-E executive and former adversary. Murderbot considers shooting her but refrains: The humans are unharmed, and Leonide is unarmed.

Farai explains that their commercial transport was diverted to the torus through bribery, and a fabricated document irregularity landed them in a labor camp. Leonide found them, warned that B-E would use the family to trap Mensah, the former leader of Preservation (a noncorporate polity), and brought them to this safehouse. Now Leonide wants Murderbot to evacuate five of her own family members in exchange for help escaping. Murderbot suspects Leonide engineered the detention in the first place; she does not deny it.

A security alert warns of an imminent raid, and two armed groups of humans and SecUnits converge on the house. Leonide reveals a concealed escape hatch beneath the floor, leading to decommissioned maintenance tunnels. The hostiles blow both doors with explosive charges that spray shrapnel. Murderbot shields Leonide, but the shrapnel embeds deeply in her torso. The group scrambles down a ladder, and Murderbot seals the hatch. Leonide’s injuries are fatal; Naja administers a final dose of pain medication. Before dying, Leonide sends Murderbot a feed packet containing tunnel maps, transport schedules, and the location and images of her family members.

As they move through the tunnels, Farai pushes to rescue Leonide’s people, noting one is a child younger than Sofi. Murderbot agrees to take its own clients out first, then return. They navigate upward through lift tubes, rest in a jungle-themed mercantile zone, and steal a tourist flyer from a closed platform. Farai pilots them into the air corridor, a massive tube along the inner ring. Through a transparent wall, they see the planet at the torus’s center, mined nearly to destruction. 

A larger private aircraft locks onto them; its crew turns out to be wealthy humans who attack travelers for sport. Murderbot subdues all seven attackers, and the group claims the better aircraft. During the flight, Farai apologizes for telling Murderbot to do whatever was necessary, saying she should have trusted its judgment. Murderbot responds that it was prepared to kill the raiders and that knowing Farai would not hate it for doing so is what mattered.

The group continues to their target zone, where they will meet their shuttle to escape the torus. Naja takes Sofi to a transit station while Farai accompanies Murderbot to the second safehouse to rescue Leonide’s family. Murderbot’s drones reveal that the adults inside are hostiles with concealed weapons, and three dead humans lie in a back room. Two children, however, huddle alive on a bunk. 

Murderbot tells Farai that the safehouse is a trap and presents a rescue plan. It goes into the adjacent apartment, following Leonide’s directions to a concealed door in the bathroom that connects to the safehouse bathroom. Murderbot enters, jams the hostiles’ communications, and incapacitates all three. Farai enters and finds the older child, Janity, chained to a bed frame. Farai frees her, and they escape with Janity and the younger child, Tula, across rooftops via obsolete infrastructure shafts.

They reunite with Naja and Sofi at the transit station and prepare to board a boat, but a B-E assault force arrives. Murderbot sends its humans aboard the departing boat and joins the local militia. It realizes that this conflict is a distraction: A larger B-E team has entered through a lower-level tunnel. Murderbot descends and finds 22 B-E soldiers below, setting explosives. It blinds them with a bright light, grabs their explosive charge, and detonates it against an underwater window, flooding the lower level. Murderbot swims out and surfaces near the boat, where the passengers pull it up, and it reunites with the family.

Over the next 27 hours, they cross multiple zones by boat, tram, and rented vehicle. Janity asks about her mother; Murderbot tells her Leonide was smart and that other supervisors felt threatened by her. On a private channel, Farai tells Murderbot that she suspects Janity was manipulated by a trusted adult into revealing the safehouses’ locations. Farai also admits that Mensah’s family has not always been fair to Murderbot; she and Tano, Mensah’s other partner, once resented what Murderbot represented about Mensah’s life away from them.

At the outer-ring port, where they are to meet their shuttle, armed B-E hostiles guard both dock entrances. Three appears unexpectedly, admitting that it reentered the torus instead of returning to the shuttle as Murderbot ordered. It also gave the governor module code to another SecUnit. Together they devise distractions: a false breach alarm and a code substitution that redirects B-E toward the wrong targets. The team passes through the dock entrance unchallenged.

Meters from the shuttle, Supervisor Tillweather, a B-E executive and Janity’s second father, calls her name. He is the trusted adult who passed the safehouses’ locations to the hostiles. He asks Janity to come home, claiming no one would have harmed the children. Janity chooses to leave, and he walks away. 

Inside the shuttle, Mensah is waiting, having been aboard the entire time, a fact Murderbot concealed in case of capture. Mensah and Farai embrace with Sofi between them. Janity and Tula watch as if they have never seen anything like it. Murderbot is quietly thrilled to see Mensah again. It goes to the cockpit, where ART-drone greets it and disengages the shuttle from the torus.