In the independent city-states of the year 2031, it’s always better not to get involved.

Burly robot repairman Mack Sullivan tries hard stay out of trouble, focusing only on his work. Haunted by the loss of his sister, Samantha, a drug user who died during the privatization era, Mack fixes up and recycles old robots, many of which are being used for security within the walls of the sovereign municipality of Rockridge.

But when Mack is hired to fix two malfunctioning Bigdog robots that are being used as watchdogs in a dirty private postal warehouse, he’s forced to reconsider his rule about not getting involved — and forced to think about what it means to help people. The decision will jeopardize the safety of everyone Mack knows, and threaten the downfall of the oppressive sovereign municipalities.