Murderbot is on a stealth extraction mission on a torus. They work their way through the different (artificial) landscapes owned by various corporations, hacking their security systems and transport systems and hauler bots and everything else they need to get the job done. And it wouldn't be a Murderbot novel without them fighting aggressive corporations, of course.
This book is less violent than the previous ones, maybe because Murderbot got a mental health module? Or maybe some of the people they're rescuing are juveniles, with their own needs and problems.
I loved it, a worthy successor of the series!