Malcolm sleeps over at Stevie's house and, appalled at his over-protected lifestyle, persuades him to sneak out to a strange, late-night escapade. Francis deals with hazing at military school. Reese tries to prove he's man enough to watch a scary movie.

Shenanigans abound at the fancy spot where the family's dining with the Kenarbans, and at Francis' school, where rowdy teenage girls are partying.

Malcolm, Dewey, Stevie, and Reese hide out at a traveling carnival after hours and run afoul of a determined security guard and several members of the freak show.

The family takes a vacation with the Kenarbans, sharing a houseboat. And while Steve's parents are caught in a fight, Reese and Steve socialize with some cheerleader from a nearby spirit camp, Malcolm is stuck with Hal fishing. At the military academy, Eric turns eighteen and leaves for Alaska, inspiring Francis to do something about his situation too.

Poker showdowns with Abe give Hal a flush; dance lessons turn Lois awhirl; an Alaskan blizzard entraps and rattles Francis. (TV Guide)

Girls in the house spell trouble for the boys, who are on their own while Dad's hosting a poker game that's more about one-upmanship than cards.

Lois gets jury duty and Hal tries to figure out what case she's working on. Meanwhile, Malcolm and Reese saw Stevie's mom naked and brag about it, they also take Dewey to the sewers and get lost.

A sex lecture from Lois rattles Malcolm; a ranch calamity unnerves Francis; disharmony among Hal's music group is a prelude to their concert. Also, a day in jail tests a defiant Reese, who faces a "Scared Straight" encounter.

Lois goes into labor while Hal and the boys are at a bridal exposition. Ida moves in after her apartment burns down and she refuses to stay with Susan.Dewey reveals the date his parents chose for the baby's planned delivery is his birthday in an announcement at the exposition to humiliate Hal.

While Lois is in labor, the house is hectic, and Hal, desperate to get home, has crashed the car on the way out of the expo.

No one wants to tell Stevie his parents are getting a divorce, until Reese spills the beans.

Hal sets up Abe Kenarben on a blind date with Jaime's babysitter Polly but then realizes Lois has also set her up on a blind date - with Craig. Malcolm, Dewey (with his "lucky" shirt) and Reese also meet Reggie Jackson and Francis is embarrassed by Piama in front of his co-workers.

When Hal and the garbageman get into a trash-dumping war (which benefits Dewey more than anyone else), Hal enlists Reese's help. Meanwhile, Lois gets her job back at Lucky Aide (off probation), and fights against Malcolm in order to take down an offensive billboard of a smiling black janitor (whose nametag reads "Slappy") holding a mop and a 6-pack of malt liquor. Soon it's an all-out war between mom and son - until Lois encounters a fellow employee who is more racist than the billboard.

Kitty returns and asks Lois for help getting Kitty's estranged husband back; Francis comes home and puts Dewey through the torturous "Brotherhood Initiation."

When Hal catches Dewey smoking, he makes a deal with him that he will stop drinking coffee if Dewey quits smoking.

Hal learns that his father has passed away, but sheds no tears and passes it off as nothing since he never knew him. So, to make sure nothing like that happens again, he lets the boys do whatever they want by letting them miss school and even offering to buy Malcolm a new car, until Lois puts a stop to it. Noticing how depressed Hal has become, his friend Abe brings George Takei over for a visit in an attempt to cheer him up.

Hal's friend Trey tells him to come to his dental office when he looses a tooth during a poker game, but their friendship becomes in jeopardy when Hal's faced with a $2,000 bill and causes a fight between them. Reese, meanwhile, teaches Lois how to ride a bike, while Malcolm and Dewey find sleeping as their new favorite pastime.

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. Meanwhile, Reese does everything he can to get a permanent job as a high school janitor, which includes creating the most disgusting mess ever. In the meantime, Hal has problems with Malcolm's Harvard tuition, while Francis finally gets a real 9-5 job that he actually enjoys. Also returning for the family celebrations is Grandma Ida, as they all say goodbye to Malcolm when he leaves for college.