Homer and Marge, on the way back from an orchestra performance, pass through a seedy part of town. Marge cautions Homer, but gets enticed by Snake's Three-card Monte game. Snake cheats Homer out of $20. Marge exposes the con, and Snake takes off. Marge and Homer chase after him, but Homer fails to catch up. Marge manages to knock Snake unconscious using a garbage can lid. The incident gives her a sense of exhilaration, she finds that her everyday routine is dull and boring, and she decides to spice up her life by joining the Springfield police force. Homer is less than enthused about her becoming a cop, but she assures him that he will remain "man of the house". Marge reports for police recruit training and performs well in the various tests, eventually becoming part of the force.
On her first day, Chief Wiggum assigns Marge to Junkyville and Bumtown. On her beat, after encountering Lionel Hutz rummaging in a dumpster, she visits the Kwik-E-Mart, where Apu tries to bribe her. On her day off, she orders Bart to wear safety equipment when skateboarding. Lisa tries to encourage Marge to attack the roots of social problems but she changes the subject with a McGriff the Crime Dog puppet. That night, Homer and his friends (Lenny, Carl, Moe, and Barney, who are joined by Herman), play a game of poker. Marge comes in and tells them gambling is illegal, and Homer's friends and Herman beat a hasty retreat.
Marge becomes unenthusiastic about her job, as everyone seems to be breaking the law - especially Homer, who has parked illegally along a disabled parking area and bought liquor for the underage bullies. Marge arrests Homer by writing him a parking ticket. While hosting another poker game and complaining about the drawbacks of Marge's new job, he finds Herman running a jean-counterfeiting operation in the Simpsons' garage. As Herman and his henchmen are about to beat him up, Marge bursts in. As she is cuffing the rest of the minions, Herman takes Homer hostage and runs to Bart's treehouse, with Marge in hot pursuit. Herman tries to escape using a pair of counterfeit jeans as a rope, but they rip and he falls to the ground. Wiggum informs Marge that they can't hold Herman due to the evidence "mysteriously disappearing", with Wiggum and the cops openly stealing the jeans for themselves. Marge gets fed up with the obvious "corruption" on the force and finally quits.