When Bender starts leaking oil, the Professor inspects his body and realizes he's missing his back-up unit... the device that allows robots to be immortal.  When Bender realizes he might have to face mortality, he seeks revenge on Inspector #5, the bureaucrat that signed off on him being okay.  Hermes helps Bender search the head main bureaucracy building where they discover Inspector #5's file is missing.  Being pursued by mom bots sent to kill Bender after he made a phone call to declare himself defective, he and Hermes go on an adventure that takes them down to Mexico where Bender was built.  After finding the guy's address and the house abandoned, Hermes talks Bender out of his revenge mission and uses a computer to declare Bender dead, therefore calling off Mom's robots.  The audience is then let in on the fact that Hermes was Inspector #5.  That's some serious mind blowing $%@.