A routine physical examination of the nuclear power plant's employees shows Mr. Burns just how vulnerable his human employees are to the damaging effects of the radiation exposure. So Mr. Burns decides to replace all the plant employees with robots, except for Homer. As the only human worker, Homer becomes quickly bored and begins messing with the robots and their programming. He ends up resetting their prime directive and they try to kill him and Mr. Burns. However, the two are saved by the unemployed former plant employees.