After a "Sithal War" re-enactment, Bender mocks the rest of the Planet Express crew for their mortality. He believes that the back-up unit he was installed with will download him into a new body once his current one is destroyed, effectively making him immortal. His irreverence for death annoys his coworkers, but he informs them that the only human being whose opinion matters to him is that of "Inspector #5", the quality control inspector at Mom's Friendly Robot Company who assessed him right after he was built. Though he does not remember him, Bender lauds "Inspector #5", believing his approved inspection to be the ultimate affirmation of his perfection. However, after discovering and fixing an oil leak, Bender learns that he is missing the back-up unit because of a production defect. Hermes agrees to join him in his quest to discover the identity of Inspector #5, leaving Leela in charge of all bureaucratic business. Unable to understand her first piece of paperwork, she hides it behind a plant.
After a fruitless trip to the Central Bureaucracy where Inspector 5's digital AND physical file were missing, a frustrated Bender calls Mom, who dispatches Kill-bots to eliminate Bender in order to cover-up the existence of a 'defective product', which would tarnish her company's image. The duo try outrunning the Kill bots on a train, but they catch up. With a very low tunnel coming up ahead, there is no choice but to limbo while standing atop the train. But Bender couldn't limbo without limbo music. Luckily, the bullets bouncing off his chassis provide the tune. After twelve hours through the tunnel, Bender and Hermes arrive in Tijuana, where they find the old home of Inspector 5. Bender gives up on his search and Hermes gives him a new outlook on life. Bender then puts Hermes on his 'Don't Kill' list (which only includes Fry). Soon, the Kill bots catch up and start destroying the building. Hermes is able to hack into the computer console and upload false information to the Kill bots claiming Bender has been eliminated; he narrowly escapes the wreckage of the house in the Kill bots' wake by limboing. Back at Planet Express, Hermes and Bender return to find it in complete chaos thanks to a panicking Leela who tried to hide every single paper behind plants.
After an hour of work, Hermes manages to turn everything to normal and burns various paperwork, among them a file revealing that he is Inspector 5; he actually detected Bender's defect when the 'infant' robot came off the assembly line. However, rather than dispose of the robot Hermes found the newly made Bender just too adorable to destroy, and chose to override the computer and allow Bender to live; he then resigned from Mom's Friendly Robot Company and left his house in Tijuana.
It is revealed he secretly stole Inspector 5's file while he and Bender were in the Central Bureaucracy; he did not have to hack into the computer at his Tijuana home because it was his in the first place. The ending scene of the episode shows Hermes having a smile on his face, proud of his decision to save Bender. The episode ends with "Little Bird, Little Bird," an American children's song, performed by Elizabeth Mitchell.