In tonight's Halloween-centric episode, Ron is forced to go trick or treating with Diane and her young daughters. When she has to leave for work, Ron ends up upsetting the girls by breaking their tiara, and then gets in an argument with Diane when he refuses to apologize. In the end, Ron ends up taking the girls trick or treating and making up with Diane.
Meanwhile, Leslie is preparing for Ben to move back to Pawnee because the campaign he worked on in D.C. was won. However, Ben is offered a new campaign to work on in Florida and must decide whether or not to take the job or move in with Leslie.
At a Halloween party, Leslie hears the news about Ben's potential job and in order to cheer her up, Ann suggests they go scare Tom when he comes out of the bathroom. Unfortunately, it's Jerry who comes out instead and has a heart (fart) attack and needs to be taken to the hospital. In order to help Jerry pay for his hospital bills, Leslie organizes a large scale garage sale.
Ann brings all of her boyfriend-related belongings to sell and Tom attempts to sell his clothes at a higher value than when he bought them. In the midst of selling a young boy a jacket, Tom realizes he can make decent money renting his clothes and invents a new business on the spot: "Rent-a-Swag."
Leslie puts Ann up at the auction, but Ann ends up bidding on herself because she doesn't want to go out with her highest bidder. After the unsuccessful sale, Leslie returns to the house she wanted to lease and informs the agent she won't be able to lease it because she assumes Ben will be taking the job in Florida.
Ben then surprises her and proposes marriage and Leslie gladly says yes.