When Lois finds her red anniversary dress burnt and in the toilet, she immediately suspects Reese, Dewey and Malcolm of foul play, and chases them all over the house to try and make them fess up, while Hal waits all night at the restaurant alone.

Because of Dewey always leaving food in the crawlspace under the house, the whole family is forced to live in a trailer owned by Lois' coworker, Craig, while their house is being fumigated. However, Malcolm ends up spending more time at the home of an upper-middle-class family who has hired him as their babysitter, but he learns that they were secretly videotaping him. He later blackmails the family to leave him alone and quits the job, also revealing a horrible secret about the family's wife. Meanwhile at the academy, Francis finds the corpse of a former janitor in the basement of the military school, who was missing for 16 years, and teams up with his friends to give the forgotten custodian a proper burial by sending him down the lake in a burned boat and performing a burial at sea, which turns into a disaster.

Hal takes the day off and the boys to the stock car races, while Francis gets into trouble with Commandant Spangler which leads to troubles with his fellow cadets, but that can not stop Francis from aiming for the next big possibility to screw up - this time it involves a Dog and a Snake. As Lois is searching for a check, she discovers more and more dirt on each family-member, hidden in the dustiest corners of the house, which she piles up for later use. Meanwhile the boys get bored at the tracks fast and get into problems on their own.

Malcolm sucks at street-hockey, frankly because he has no skates. So he turns to his father, who trains all his sons in the secrets of skating before he allows them to have their own pair. Neither of his bigger brother tell him about his fathers training and Malcolm gets even more anxious as Hal gets very mysterious about it all, but nothing can prepare either one of them for what is to come. Lois hurt her back terribly and has to stay in bed, which does not keep her from tyrannizing Reese and constantly trying to avoid being drugged with pain medication by her loving husband Hal. At the military academy everybody is preparing for a weekend of survival training without any comfort, except for Francis who tries to ditch his comrades.

Lois takes off to visit Francis at the academy, which might make his recent appendectomy just a little more painful. Without Lois, Hal devolves to his former bad boy personality, which turns the robot Malcolm builds with his Krelboyne colleagues into a much more destructive power than expected.

Commandant Spangler announces his mother's visit and Francis uses the opportunity to organize a dance, for which he invites some local girls, which ends up to be a very different experience then the cadets expected. Meanwhile the Kenarbans invite the whole family to a nice dinner that turns into an evening of conflicts, as the families get to know each other better.

In an attempt to avoid the worst moments of medieval week at his Krelboyne class, Malcolm spins a delicate web of deception for the school therapist. Francis takes over the laundry at the academy and Hal discovers that his youngest, Dewey, is a natural at skittles.

Malcolm accidentally hits a ball into grouchy old Mrs. Griffin's yard, and when he goes to retrieve it, he has a run-in with the elderly lady that accidentally makes her fall and break her arm. As punishment, he must go over to her house every day after school to help her out. Meanwhile, Dewey begins to carry a purse to school instead of a backpack; and Francis must deal with his screw-up friend Richie at military school.

Lois' estranged parents, Ida and Victor, pay the family a visit. Right away, trouble starts brewing. Victor bonds with Reese, Ida gets Malcolm into a fight, and Dewey is haunted by childhood memories of his inattentive grandparents. To make matters worse, Grandpa Victor gives Reese a live grenade as a present, and worse comes to worse, the boob pulls the pin! Luckily the family survived the explosion, but their brand new, expensive refrigerator wasn't as lucky.

Francis organizes a hunger strike to get back the academy's TV, taken away by Commandant Spangler. Meanwhile Malcolm has to go to the hospital, leaving him in the children's ward and the family without their genius middle son.

In this episode Craig still lives in Lois and Hal's house, because his one had been burnt down. That costs a lot of things on the whole family. Meanwhile, Malcolm and his brothers find a mini-bike in the garbage. At first they argue with each other, but after their mother banned the use of the bike, they join forces against her. At the same time Hal goes to Allabama to visit his son Francis for the Fathers-and-Sons meeting, where he expects some great achievements from his son. But what will happen after all that ?