Christopher Lloyd adds to his gallery of eccentric characters, playing Hal's quirky, cranky and very wealthy father, Walter, in this rollicking episode. The occasion is a birthday celebration for the old man, but the snooty female in-laws seem more interested in offending Lois. Their shabby behavior initially goes unnoticed by Hal, who's desperately trying to bond with his self-centered dad; and by Dewey and Reese, who seek some of Grampa's dough by currying favor with him. But when Lois is reduced to tears after being excluded from a group photo, the family rallies to her side with an all-out counterattack that turns the party into pandemonium.

Malcolm and Reese go to a bowling party where they vie for the attention of a cute girl.

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.

After being rattled by a battle among the boys, a pregnant Lois ponders the consequences of raising another brawling kid. So she fantasizes that her unruly sons have morphed into well-behaved young daughters. Malcolm becomes Mallory, Reese is transformed into Renee and Dewey turns into Daisy.

When four popular high school girls play an evil prank on Reese by pretending he has a secret admirer and then dropping a pig off at his front door, Lois comes to his rescue. She plots her revenge on the four unsuspecting girls and wreaks havoc on their adolescent lives. Meanwhile, Hal realizes Lois is at a dangerous emotional place so he decides to get some distance and stumbles upon the idea for making his own pitching machine out of stuff in the garage.

Lois is two weeks late with her period, causing her and Hal to panic and start a big fight, while trying to keep it from the boys. And while Dewey is scared that his parents may split up, Hal and Lois remember the troubles of getting their previous four sons.

Highway horror: Reese gets a learner's permit, which he promptly proceeds to abuse by commandeering a driving-school vehicle.

Hal is inadvertently responsible for a toxic chemical spill that forces a neighborhood evacuation; Malcolm deals with being grounded even in the emergency shelter; Francis suffers through a date with a geeky 12-year-old.

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.

Reese continues to be a great soldier in the Army until he finds himself in a situation where his Sergeant cannot help. But after comparing being captured to being grounded, he takes action and leads his team to victory. But being such a successful soldier has it's bad parts as well, as Reese prepares to jump from the plane - right into Afghanistan. Malcolm has his hands full as well as he attempts to prove Hal innocent. But being good with numbers helps as Malcolm notices all of the prosecutions given dates are on Fridays - which Hal hasn't worked on in over 15 years. And with Reese missing and Hal's case, Lois falls deeper and deeper into insanity.

When Lois catches the boys vandalizing a trashy billboard for a strip club, Malcolm alters the vandalism into a women's rights protest, which sparks a colossal media circus. In no time, feminists, conservative religious groups and national new reporters descend on the scene. After Hal grants a TV interview, a woman from his past turns up at the faux protest; and Reese, inspired by the giant billboard stripper who comes to life in his dreams, gives an impassioned speech about the objectification of women.

Roller-skating lessons from Hal bug Malcolm, who rebels against dad's discipline while mom agonizes in bed from a backache she blames on Reese. Francis avoids his squad's survival weekend.

Malcolm gets a job working for Lois on the drugstore loading dock but is shocked to find that Lois smokes. She makes him promise not to tell, then turns her back on him and writes him up for a silly offense. Meanwhile, Dewey runs away to the Ranch to be with Francis because he says he is tired of Reese and Malcolm. Hal is also busy, secretly betting on and entering Jaime in baby competitions.

After Hal forbids Dewey from inviting his peculiar classmate Chad over for a sleepover, Dewey quickly finds out that his father had good reason to warm him. Meanwhile, Malcolm and Reese find out that they are not as popular as they once thought, then plot "revenge" on their classmates.

Reese and Malcolm try to perform the ultimate Halloween prank.

Malcolm convinces Dewey to do poorly on an I.Q. test, so that he won't become a ridiculed Krelboyne student. But Dewey does so badly that he is placed in a class for the emotionally disturbed. Hal and Craig compete in a dance competition.

When Lois buys a brand-new king-sized bed, Hal thinks that her motive is to put more distance between them and refuses to sleep in it. Moved to tears by an opera he sees on television, Dewey is inspired to write his own operatic masterpiece, "The Marriage Bed," which is based on his parents' fight and turned into a school production. Meanwhile, Malcolm and Reese build their own street luge board; and Jamie falls head over heels for the baby girl across the street.

Reese befriends a pack of troublesome stray dogs; Dewey feels conflicted when he starts seeing another mother-figure; Hal unwittingly becomes a motivational speaker.

Unbeknownst to Lois, the boys enter her in the Mrs. Tri-County Pageant as a joke. When they overhear the other contestants remarking that Lois doesn't have a chance of winning, they plot to help their mother take the crown. Meanwhile, Malcolm is blackmailed into delivering love notes to a contestant for Herkabe, and Reese discovers that, according to the Mrs. Tri-County Pageant manual's scientific formula, he is beautiful.

The whole family attends a Krelboyne family picnic, and Malcolm dreads his performance in the event's Academic Circus will make him look like a freak. Disasters abound as stage acts bomb, families feud, and Malcolm's dad serves meat to vegetarians.

When the family goes to a water park for a day, Dewey is left home with an elderly, stern babysitter. Francis is hustled at pocket billiards by his military-school commandant.

Crummy gifts rile birthday gal Lois, who suddenly splits from home, leaving confusion, anxiety and desperation in her wake.

Malcolm skips out on Thanksgiving to go to a party; Reese becomes abusive to Hal and Dewey as he attempts to prepare Thanksgiving dinner.

Malcolm joins a local dance class to impress a girl, but when she loses her footing, he realizes that to win the competition he'll need a partner who can step it up. Dick, a rival student in the class who takes dancing a bit too seriously, challenges Malcolm to a dance-off. Meanwhile, Hal discovers an underground bachelor pad in the backyard.

When Stevie goes to the hospital, Malcolm tries making up every excuse he can think of to not go because he can't face the truth about his illness. Meanwhile, back home, Hal gets highly competitive about his new remote control boat, while Lois thinks she's going insane.