A rogue SecUnit that privately calls itself Murderbot, its governor module hacked long ago, once saved Dr. Mensah's PreservationAux survey team from GrayCris, the company that massacred the rival DeltFall expedition to hide an illegal harvest of alien remnants. Mensah bought its contract out of Company inventory rather than let it be scrapped, then let it go when it chose its own future over a guarded life on Preservation. Traveling alone, it fell in with ART, a media-obsessed research transport that rebuilt its body to pass as an augmented human and became its first friend; together they proved the fifty-seven people Murderbot killed at Ganaka Pit died because sabotage malware drove every unit berserk. It parted from ART with a comm link and one instruction: find your crew.
This book began with Murderbot traveling as Security Consultant Rin, until a newsfeed interview showed an exhausted Dr. Mensah urging an investigation into Milu, the terraforming project GrayCris abandoned outside the Corporation Rim. Sure the terraforming was a cover for illegal alien-remnant mining and that the facility was meant to fall into the planet with the evidence inside it, Murderbot rode a supply hauler out of HaveRatton beside the security consultants Wilken and Gerth, trailed them to a GoodNightLander Independent assessment team under Don Abene, and got onto their shuttle by befriending Miki, Abene's human-form bot and adopted family. On the storm-wrapped facility it copied the diggers' logs into clips implanted in its forearm, then blew its cover saving Abene from a retrieval device that carried off the researcher Hirune. It fought a combat bot, hijacked thirty drones to steal Hirune back from two more, and returned in time to freeze Wilken's powered armor after she grabbed Abene by the hair and Miki lost a hand blocking the shot. In this last stretch, holed up in the geo pod while Miki dug shrapnel out of its back, Murderbot and Abene worked out the real plot: Wilken and Gerth were never hired to kill anyone, only to send an encrypted signal that would launch a work zipper carrying the fourth combat bot at the tractor array, so the whole facility and all its evidence would drop into the atmosphere. It drove three diggers at the shuttle to panic everyone out of it, froze Gerth's armor as she emerged, got the crew back aboard under fire, and undocked; then Brais's plan to shove the zipper off course with the shuttle saved the array with forty-five seconds to spare. The last combat bot punched through the airlock anyway. Miki refused Abene's order to save itself, declared that its priority was to protect its friends, and threw itself at the bot so Murderbot could drive a core cutter through the thing's processors. Miki's chest was crushed. Murderbot sealed itself into an evac suit, left the locker open so the crew would think it had been blown out in pieces, and jetted away to its supply ship.
It drove three diggers at the shuttle to panic everyone out of it, froze Gerth's armor as she emerged, got the crew back aboard under fire, and undocked; then Brais's plan to shove the zipper off course with the shuttle saved the array with forty-five seconds to spare. The last combat bot punched through the airlock anyway. Miki refused Abene's order to save itself, declared that its priority was to protect its friends, and threw itself at the bot so Murderbot could drive a core cutter through the thing's processors. Miki's chest was crushed. Murderbot sealed itself into an evac suit, left the locker open so the crew would think it had been blown out in pieces, and jetted away to its supply ship.
Right now Murderbot is alone aboard Ship, wounds patched, on course for the wormhole and HaveRatton, checking Wilken's gear for tracers. Don Abene and her crew are limping back to the transit station with Wilken and Gerth captive as witnesses, believing the SecUnit died with Miki. Murderbot cannot stop thinking that Abene's first instinct in the crisis was to tell Miki to save itself, that she genuinely loved her bot, and that Miki, who could never really have been its friend, chose to die anyway. In a hidden pocket of the assassins' ammo bag it has just found identity markers and an unfamiliar brand of memory clip, and what is on them is very interesting. It hates caring about things, but apparently once you start you cannot stop. The geo pod data is not getting transmitted to Dr. Mensah from a safe distance after all. Murderbot is taking it to her in person, and it is going back.