Previously, on an isolated planetary survey contract, the SecUnit that calls itself Murderbot was already secretly free, its governor module hacked and its attention on its serials, until something began killing survey teams. Protecting Dr. Mensah's PreservationAux group, it uncovered deleted hazard data, the DeltFall expedition slaughtered by SecUnits under combat override modules, and an illegal GrayCris operation stripping alien remnants from the planet; when its rogue status and an older accidental massacre came out, Mensah and her people trusted it anyway. Nearly destroyed shielding Mensah from the beacon blast that brought rescue, it woke to find she had bought its contract and Pin-Lee had won a court order preserving its memory, then walked away alone rather than go home to Preservation, wanting what came next to be its own choice.
This book opened a few cycles later, with Murderbot riding a bot-driven university research transport whose overbearing mind identified it as rogue, demanded company for its media, and got named ART, for Asshole Research Transport. It went to RaviHyral Mining Facility Q Station to learn whether the massacre it committed thirty-five thousand hours ago came from governor module failure or its own choice; ART reshaped its body and named the site: Ganaka Pit, fifty-seven dead, listed as equipment failure. To land it hired on as Eden, security consultant to technologists Rami, Tapan and Maro, whose research Tlacey Excavations stole and offered back in person. Tlacey tried to kill them with killware aboard the shuttle and three men in a tunnel, while her ComfortUnit pinged for SecUnits. Alone in the tunnels, it reached Ganaka Pit and learned that sabotage malware meant only to stall hauler bots had driven every SecUnit, bot and drone there insane. Tapan then slipped off the shuttle home, lured by a friend claiming to have the stolen files; while Murderbot hid her, the ComfortUnit came to the door with a newsburst about an unsecured SecUnit at large, proposed killing every human on the moon, and left malware carrying three words: please help me. The friend's meeting was honest, but Port Authority pulled Tapan off her shuttle and the ComfortUnit led Murderbot aboard Tlacey's private shuttle, where the combat override module it carried could not work: ART had disconnected the dataport. Murderbot let ART seize the shuttle, took the compartment apart, disabled the ComfortUnit and forced Tlacey to order it to obey, then found a panicking bodyguard had shot Tapan, put her in the medical suite, scrubbed every trace with drones, and sent the shuttle back down full of unconscious survivors, a trick from Sanctuary Moon. It then rode the feed into the ComfortUnit's brain, nulled its governor module and told it to go away and hurt nobody, not for its sake but for the four ComfortUnits who died at Ganaka Pit trying to save everyone.
The friend's meeting was honest, but Port Authority pulled Tapan off her shuttle and the ComfortUnit led Murderbot aboard Tlacey's private shuttle, where the combat override module it carried could not work: ART had disconnected the dataport. Murderbot let ART seize the shuttle, took the compartment apart, disabled the ComfortUnit and forced Tlacey to order it to obey, then found a panicking bodyguard had shot Tapan, put her in the medical suite, scrubbed every trace with drones, and sent the shuttle back down full of unconscious survivors, a trick from Sanctuary Moon. It then rode the feed into the ComfortUnit's brain, nulled its governor module and told it to go away and hurt nobody, not for its sake but for the four ComfortUnits who died at Ganaka Pit trying to save everyone.
Right now Tapan is awake and patched up, holding a memory clip of her recovered files, splitting the blame with Murderbot over who should have listened, outside the embarkation zone with her collective at her back, bound for a transport within the hour. Rami has paid it with a hard currency card, Maro hugged herself because it cannot bear to be touched, and ART, disengaging from the lock, told it to keep the comm interface, be careful, and find a crew. So Murderbot walks away down the mall in the clothes ART made it, aiming for a cargo transport heading the right direction, the truth about Ganaka Pit in its memory and no relief in it: the revelation fixed nothing, and it has no idea whether it will go on with its plan, where it belongs, or what it wants now that the Corporation Rim knows an unsecured SecUnit is loose.