It's still summer-vacation time on the jaunty third-season opener, which finds Malcolm and his rowdy clan cruising on a lake in a houseboat with Stevie and his straitlaced parents, Abe and Kitty Kenarban. Some vacation. The vessel itself is a fright, a weathered heap that Dewey hates from the get-go because "There's no TV! There's no TV! There's no TV!" An equally distraught Malcolm is shanghaied by Hal for a fishing expedition, leaving lucky Reese the chance to trawl for bikini-clad beauties at a nearby camp. Back on board, the close quarters are slowly driving Abe off the deep end.

Still reeling over Francis' break for freedom, Lois and Hal find themselves face to face with their newly independent son. While at home, Francis wins back Hal's support, but Lois is a completely different story. Also, Malcolm and the Krelboynes meet their match when a new teacher "a former Krelboyne himself" is assigned to the class. He sets up a ranking system that pits the students against each other and eventually drives them to the brink of insanity.

Lois joins a book club to escape the horrors of her home life and Hal frets about how to make the boys behave in her absence. Meanwhile, Francis hitch-hikes through Canada.

Malcolm has a new light in his life: a perky classmate named Sara (whose face, in a quirky touch, is never shown). But, according to Malcolm , she's "good-looking and smart and cool. And if we went out together, it would make me happy. So therefore, it will never happen". Ah, but it doesâ-a surprising turn of events that elates the lad and perturbs his parents, especially when Malcolm goes into an academic tailspin. And it's not long before our lovesick hero admits that he's becoming "obsessive and neurotic, and a totally jealous creep".

In an effort to contribute to society and to make her boys useful at the same time, Lois "volunteers" Malcolm, Reese and Dewey for charity work at a local church. The boys are assigned to sort giant piles of donated clothing, game, appliances etc. Initially irritated at their new task, they realize the donated stuff is a lot nicer than their own possessions, and they begin swapping out their old stuff with the second-hand items. The boys soon make a enterprise out of their charity assistance, going as far as to sell things to the neighborhood kids - that is until Hal finds out. Meanwhile, Francis must come to grips with the fact his fabulous job in Alaska is not quite what he expected.

When Hal's doctor discovers something suspicious during his routine check-up, Lois and Hal become frantic, nervous wrecks as they wait for the test results. As a result of her anticipation, Lois becomes even stricter with the boys, leaving them to misinterpret the new house rules. Meanwhile, in Alaska, Francis comes to blows with his boss.

When Malcolm and his brothers destroy their Christmas tree ornaments, Lois punishes them by canceling Christmas and moves all the presents into the garage. The only way she will reinstate the holiday is if the boys behave impeccably up to Christmas morning. Her plan works better than expected, and Lois is touched that her family responded so well to her challenge. Meanwhile, the boys decide that Lois could use this tactic for future holidays and retaliate by breaking into the garage and opening up all the presents. Elsewhere, Francis is forced to visit his Grandma Ida for Christmas.

Hal and Abe fall out over a poker game, Francis gets trapped in a remote cabin during a blizzard and Reese trips the light fantastic at a dance class.

Reese is accused of stealing by his devious boss when he takes a job flipping burgers to pay for his car insurance. Malcolm is disgruntled when a genius joins his class, and Dewey must prove he can keep a goldfish alive before he gets the chance to own a puppy.

A secret shopper evaluation leads Lois to make dramatic changes to her personal appearance and in the process causes some unintended consequences. Meanwhile, the boys engineer a way to finally beat Hal at basketball and Francis becomes Alaska's premier rat catcher.

Juicy guest casting and ingenious plotting enliven an hourlong episode that airs in the plum post-Super Bowl slot. One storyline unfolds at Hal's company picnic, where Lois clashes with a blabby wife (Susan Sarandon) and her beleaguered spouse (Kaczmarek's real-life husband, Bradley Whitford); and Hal runs afoul of his new boss (Stephen Root) and the big cheese (Patrick Warburton). In Alaska, Francis's scheme to win a bet involves rigging a hockey game that pits loggers vs. a fearsome women's squad led by a blowhard coach (Terry Bradshaw).

After Hal is mistaken by his new boss, as that guy's boss, Hal plays along. Malcolm is in a three-legged scavenger hunt with the girl he likes, but becomes upset after he confesses he likes her, and she says she likes another boy. Reese is also the the scavenger hunt, and at first doesn't like the big dumb bully he is with, but they grow to like each other when they bond over beating up the other contestants and stealing their items. Lois continues to balance keeping Dewey intact and dealing with the crazy woman, but now must talk to the husband as well. Francis continues to sabotage his own team, this time on the ice.

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

Dewey helps Hal overcome his fear of kites, Malcolm reveals Cynthia's big secret, and Francis finds a totem pole unusually interesting.

The arrival of Francis's new bride on Hal's birthday sparks a fray that drives the younger siblings out - and into a posh hotel.

Dewey is appalled when Hal takes over as coach of the soccer team, and Malcolm gets more than he bargained for when he sets his computer to act out the lives of his family. Reese resorts to blackmailing his neighbor Ed, and things get heated during an ice-fishing trip.

Hal's planned night of romance with Lois is put on hold when she has to cover for Craig, who is sick, and ends up infecting both of them with his sickness. It's then a game to see who can pretend to be healthiest the longest.

Meanwhile, Dewey brings home a dog, and with his brothers ratting him over wanting to keep it, he trains it to attack Malcolm and Reese.

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.

An embattled psychiatrist probes the boys' naughty behavior patterns in a session framed by flashbacks to past episodes.

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.

The Krelboyne whiz-kids are forced to integrate with various posers, goths and other cliques in the general school crowd, while Hal and Reese race to knock down Dewey's dominoes.

Craig is held captive in his wheel chair by his new caretaker - a capuchin monkey - and Reese takes control of the neighborhood watch after apprehending an intruder.