Story so far

Murderbot is a rogue SecUnit, a part-organic, part-machine security construct built and leased out by the Company, which hacked its own governor module and has spent the years since choosing its own actions and hiding the fact. On a planetary survey it saved Dr. Ayda Mensah and her PreservationAux team from GrayCris, a corporation illegally mining alien remnants that had erased the hazard data, sabotaged the systems, and massacred the rival DeltFall expedition with combat-override-controlled SecUnits; when its own freedom and its history at Ganaka Pit came out, Mensah's people chose to trust it anyway, and Mensah bought its contract outright so that no one could own it. Then it walked away from her offer of a home, because it wanted its future to be a thing it chose rather than a thing it was given. Traveling alone toward RaviHyral to find out whether it had really murdered fifty-seven people at Ganaka Pit, it fell in with an enormous, media-obsessed university research transport it named ART, which saw through its disguise, rebuilt its body so it could pass for an augmented human, and became the closest thing it has to a friend; together they proved that sabotage malware, not Murderbot's choice, had caused the Ganaka Pit massacre, and Murderbot freed an enslaved ComfortUnit in memory of the units who died there before parting from ART, which told it to keep their comm link and go find its crew. At Milu it gathered the evidence that exposed GrayCris's fake terraforming operation as an illegal alien-remnant mine, and there it met Miki, the freely-choosing bot belonging to Don Abene of GoodNightLander Independent, who was treated as family and who died throwing itself at a combat bot to give Murderbot an opening; Murderbot faked its own death and went looking for Mensah with the proof. It found her held for ransom by a desperate GrayCris inside the corporate hub TranRollinHyfa, allied with Pin-Lee, Ratthi, and Gurathin to run a fake-ransom gambit, fought her free through the station underlevels, made a doomed last stand at the port against Palisade SecUnits and a Combat SecUnit that answered its offer of freedom by saying it wanted to kill it, and destroyed a conscious neural-tissue Attacker aboard the rescue gunship at the cost of a catastrophic system failure. GrayCris was exposed, sued, and torn apart by the bond company and everyone else it had cheated. Rebuilt on the ancient refugee ship that became Preservation Station, and offered a home, options, and time by Mensah, Murderbot half-planned to leave and chose to stay, still trying to work out what it actually wants.

Network Effect opens with Murderbot on contract as security for a Preservation survey run by Dr. Arada, whose marital partner Overse works the facility's command center, alongside Dr. Ratthi, the linguist Dr. Thiago, who is married to Mensah's brother, and Mensah's teenage daughter Amena. They are working a water world out of a mobile sea research facility. There is no planetary feed. The team has spotted eleven separate groups of strange humans in boats and been contacted by two of them, both of which Thiago calls unusually divergent and others call deeply weird; both took elaborate care to approach visibly unarmed and wanted to trade supplies, and Thiago asked them to trade stories about how they came to be on this planet instead. Arada is a terminal optimist who would simply have given them what they needed; Thiago belongs firmly to the school of thought that would rather investigate a dark cave without a pesky SecUnit along, and Murderbot knows it, because back on Preservation Station he told Mensah he had serious reservations and she told him she trusts Murderbot with her life, literally, and would withdraw her permission for Amena to come at all if anyone else were providing security.

A third boat approaches the sea facility unlike the earlier local groups: its crew is better equipped and aims a heavy projectile weapon at the researchers. Thiago ignores the agreed security protocol and goes onto the observation deck, forcing Murderbot to pull him back; the raiders shoot Murderbot into the water instead. It circles beneath their boat, climbs aboard from the stern, and quietly disables crew members while Thiago stalls their leader. Although it could kill the exposed attackers, Murderbot redirects its drones toward arms and hands because Arada would not want deaths, then broadcasts a violent serial clip through the raiders' feed to frighten them. It bursts onto the bow and disarms most of the crew, but their leader grabs Thiago as a hostage. As Murderbot maneuvers for a shot, Arada fires first and wounds the leader through a gap in his armor. Murderbot frees Thiago and throws the man back aboard. When the raiders' weapon begins charging again, Overse raises the supposedly stationary research facility on its force drive, swamping their boat and breaking its targeting lock. Everyone aboard the facility survives, though Murderbot returns inside carrying two projectiles and very little patience for Thiago's judgment.

The facility is lifting out of the water with everyone aboard alive, the raiders scattering, and their gun crew unconscious or crawling. Murderbot has two projectiles in it, a survey-logo shirt full of holes, and a badly depleted drone complement, and it is not sorry. Thiago, who did not trust its situation assessment and nearly got himself taken hostage proving it, has just been dragged out of the consequences by the SecUnit he objected to; Arada, the optimist, has just shot a man; and Amena, whose mother let her come on this survey only because Murderbot would be guarding it, is somewhere inside. This planet has no feed, eleven boat groups nobody has identified, and at least one crew willing to open fire on researchers because it wanted people rather than supplies. The survey is nearly over, the humans still argue about whether Murderbot should be calling anyone a target, and Murderbot is standing inside a hatch with two holes in it, waiting to find out whether anyone out there is going to follow them.