Malcolm and Reese attempt to escape the family and trek to Burning Man, but when Lois and Hal find out, they make a family trip out of it. As Hal goes about his routine, the crowd believes he's doing a performance art piece. Malcolm falls in with a female Shaman, Lois falls in with a tribe and Reese tries everything.
After forgetting to pay the health insurance bill, Hal locks the boys in their room to try and keep them safe, but his plan backfires. Lois contemplates a Lucky Aide union on her ten year working anniversary.
Hal tries to make an arrangement with Dewey, he'll quit coffee if Dewey quits smoking. Reese and Stevie square off.
Malcolm and Reese learn that their house was the site of grisly murders while out on a Halloween death tour. Hal freaks out when he learns it's the truth. Lois misses trick or treating because of a shoplifter.
During Jessica's weeklong stay, Malcolm learns how to better manipulate Lois. Reese tries to mail himself to China in order to confront a pen pal. Hal becomes an enemy of the bees after he destroys a nest.
Malcolm starts a secret romance with his chemisty partner Vicki when she reveals that she's actually smart. Seeing how poorly he's treated publicly, Jessica confesses feelings for Malcolm. Unfortunately for Malcolm, Jessica then tells him that was all a lie to get him to break up with Vicki.
Francis makes a surprise visit home, just as the electricity goes out in the house. Meanwhile, Malcolm gets into some trouble when he brings home a trio of Swedish beauties, and Hal decides to forego an anniversary dinner with Lois in favor of a meal prepared by Reese.
Orthotics change Lois's outlook, but when Hal feels left out, he sabotages them. A female friend from the Army comes to visit Reese and winds up with a crush on Lois. Reese thinks she has a crush on him and makes a move on her.
Lois starts to find the new babysitter annoying when she won't stop complaining. Malcolm is pained by Herkabe's mistreatment of Reese in class. Hal tries to help Dewey with a girl.
Malcolm has an awful school picture. Hal and Lois get ahold of a fellowship check for ten thousand dollars sent to Malcolm. Reese makes himself at home at a retirement community.
Ida is called in to watch Malcolm and Reese when Lois and Hal accompany Dewey to a piano competition. Ida pits Reese and Malcolm against each other with a bride as a prize. Lois and Hal learn, upon their return, that Reese has eloped to Las Vegas.
Dewey finds out that Francis is broke and suggests that he find employment. Hal meets with college recruiters when Malcolm decides not to.
Lois passes Mono along to Malcolm and they're forced to co-inhabit a quarantine in her room. Hal is bored when Lois tells him to not bother her, but his boredom is abated when the neighborhood welcomes him with open arms. Hal learns he hasn't been invited to things because of Lois.
Hal greets news of his father's death without tears and Lois worries that he's holding it all inside. Hal worries about how his boys will treat his own eventually death.
Hal and Lois go to see Francis and join him for an A.A. meeting, where Hal learns that Lois was the one who got him drinking to begin with. Meanwhile, Dewey attempts to get Malcolm and Reese to give him a ride to the local arcade.
Lois swoops in and unleashes her cunning on four high school girls who decided to humiliate Reese. Meanwhile, Hal decides to get away from Lois for a bit and ends up building his own baseball pitching device.
Hal loses a tooth while playing poker with the guys, but when his dentist buddy Trey decides to do some work on him, Hal gets a huge dental bill which could sever the friendship. Meanwhile, Dewey and Malcolm embrace sleeping, while Lois tries to master bicycling under Reese's tutelage.
Malcolm tries to look good to a girl by joining a dance class, but finds himself competing against a cocky classmate in a competition. Meanwhile, Hal stumbles upon an underground pad in his background designed for the single guy.
A worried Malcolm tries to avoid going to see Stevie in the hospital when his illness gets progressively worse. Meanwhile, Hal begins to get intense with remote control boating, while Lois worries that she's losing a grasp on her sanity.
When Reese heads back to his job at the meat market, he meets an attractive vegetarian, who he thinks is quite the catch. To impress her, he pretends to be a vegetarian until he's caught with a juicy pork chop. In an effort to gain back her respect, Reese decides to go back to the meat market and let all of the cows go free. Meanwhile, Malcolm is trying to sneak off to a rock concert.
Malcolm struggles with his speech when he's elected valedictorian of his graduating class at school. However, Lois refuses to listen to any of his complaints and reveals that she wants him to become President of the United States.