The family is forced to live in a trailer in their front yard while their house is fumigated; meanwhile, Malcolm becomes a babysitter for a rich family, Francis finds an old corpse at military school and gives it a proper send-off.
Malcolm, Reese and Dewey are polite and courteous while playing violent games, but as soon as Lois turns them off, the brothers squabble and fight with each other. Lois punishes them, sending the boys to bed without properly getting ready. She tells them that "Only boys who behave get to rinse!" Hal notices a hole in the wall and pries it open, only to discover an insect infestation. The exterminator blames it on the candy wrappers and half-eaten food in the crawlspace, speculating that "some creepy hobo" has been staying there. Lois and Hal immediately realize that the "hobo" is Dewey. The entire family moves into a trailer they borrowed from Craig in the front yard while their home is being fumigated. Malcolm wonders why the family can't stay in a hotel, and Lois replies that they're giving all their money to the exterminator so they can stay in nice hotels. Hal and Lois begin fighting profusely for some reason, the reason of which Hal realizes later in the episode: the family's new and temporary close quarters have affected Lois and Hal's ability to make love, which is what keeps them benevolent towards each other. Hal purchases gas masks for him and Lois so that they can safely enter the chemically poisoned home and release their frustration.
Malcolm's cushy babysitting job that earns him more money than his parents make provides relief from the trailer, until Malcolm learns that the trust placed in him in his new position is strictly limited. Although the parents confided in Malcolm that they considered him part of the family, he gets the TV remotes mixed up and accidentally switches to a channel that's broadcasting security camera footage that shows Malcolm's every move. Malcolm tells them off by pretending to begin to blend their prized pet fish in a blender and then quits, which the parents witness as they're reviewing the footage from when they were away. This behavior makes Malcolm treasure his own family more, because "with them, at least you know where you stand."
Meanwhile, the military school's master key leads Francis to a corpse, for which he feels obligated to provide a proper send-off. After his military school buddies disrespect the cadaver by partying around it, Francis convinces them to set the body afloat on a flaming boat like Vikings used to do, right before he rips off what he thought was a fake joke mustache on the body. The fiery boat in which they place the body was doused with too much gasoline and one of Francis' classmates accidentally leaves the gas can on the boat. Eventually, the boat explodes and crashes into the boat house, setting it on fire. Francis and his comrades run away as fast as possible to avoid trouble with the Commandant.
- It is revealed in the beginning that the boys are nice and calm to each other when playing violent video games, but when Lois changes the game into educational television, they all got annoyed with having to watch it and then actually started fighting. This is most likely a parody of the controversy at the time, that said that violent content in children's media, promoting violence in real life.
- It is revealed that before he started dating Lois, Hal was in a relationship with her sister, Susan Welker. This would be the first time in the series that Susan was ever mentioned.
- Dewey farts in the swimming pool where Reese and Hal get out right away.