On a trip to Springfield's bimonthly science fiction convention, Homer sees Mayor Quimby and Mak Hamill get surrounded by rioting attendees. Unwilling to stand by and watch them get mobbed, Homer safely escorts them out of the fracas. Mayor Quimby is impressed, and he makes Homer his bodyguard.

Homer begins watching over the mayor. As he accompanies Quimby throughout the town, he chooses to look the other way as the mayor receives bribe after bribe. At a meeting in which Quimby grants Fat Tony Springfield Elementary's milk concession, Homer makes a shocking discovery: Fat Tony is supplying the school with rat milk instead of cow milk. Disgusted, Homer confronts Quimby and accidentally knocks him out the window. Discovering Quimby hanging on the ledge, Homer makes him promise to expose Fat Tony in exchange for pulling him back.

Knowing Quimby will be in danger from Fat Tony, Homer vows to protect him. At a production of Guys and Dolls starring Mark Hamill, Fat Tony has his henchman, Louie, try to kill the mayor. Louie first gets into a scuffle with Hamill before trying to stab the mayor. Homer grabs Louie just in time, and they fight. With Hamill's help, Homer subdues the gangster. But he soon discovers that while he struggled with Louie, Fat Tony savagely beat Quimby with a baseball bat.