Lois, Hal and the boys take a road trip to Las Vegas to support Dewey in a contest for his Junior Farmers of America Club. Malcolm, to make up for telling his mom that she embarasses him, gets Lois tickets to see her favorite performer, the incredibly cheesy Boone Vincent. Hal tries to relive a dream and win a jackpot. Reese shows off Dewey's incredibly fat rabbit, but then has to save it from a restaurant kitchen. Francis, trapped in a well with Otto, worries that he's been screwing up around the ranch. More...

Hal forces a sleep-deprived Lois to go to bed, but Lois, in her deep sleep, falls off the bed and ends up almost choking on a dust bunny on the floor. Hal leaves the boys to take care of Jamie while he goes to get diapers. When Craig busts him stealing diapers from the store because he's low on cash, Hal finds himself working off his debt and, eventually, leading an employee revolt. A trio of hot girls come to the door in a limo and steal Reese, Malcolm and Stevie, the three biggest losers they can find to make their jerk boyfriends jealous. Dewey, left in charge of Jamie, tells the baby an entertaining story about their parents' secret lives. More...

When Abe's wife leaves him and Stevie, Stevie regresses and refuses to move or speak. Malcolm's efforts to cheer up his friend land him in a wheelchair... just in time to be Stevie's partner for wheelchair basketball. Hal becomes Abe's new wife. Reese finds a girl's diary and, while reading it, falls in love with her, but he is horrified when he finds out that it's his mother's. Dewey decides he wants to be a baby again. Francis and Otto struggle with putting down one of the horses. More...

Malcolm is excited to finally have some normal friends, including a cute girl named Kirsten who flirts with him by insulting him. He skips out on the family Thanksgiving to go to a party, has a few beers, and finds himself about to have sex with Kirsten when he realizes that she's too drunk and he can't take advantage of her. Reese tries to cook a Thanksgiving masterpiece, including a turkey stuffed into a monkfish, but soon runs off his assistants, Dewey and Hal, by mistreating them. Francis and Piama, visiting for Thanksgiving, have had a big stupid fight, and are talking about getting a divorce. Hal worries about Lois meddling, but when it looks like Piama is going to leave without Francis, Lois uses a little brilliant reverse psychology to mend their relationship instantly. A drunk Malcolm returns home just in time to ruin Reese's Thanksgiving feast by throwing up on it. More...

Lois hopes to buy a new washing machine with Hal's stock options, because Hal thinks his long-awaited company merger is about to happen. Instead, all the executives of Hal's company are arrested for fraud. Dewey skips school to be a street magician, and secretly makes mad cash. He is depressed when his parents find his stash, think it's a God-send, and use it to buy a new washing machine. Mr. Herkabe convinces Malcolm to do a secret study on his brother, Reese, for a psychology project, but then turns around and makes Malcolm the subject of a study about what people will do under orders from a superior. Reese's secrets are made public to the school, and he is humiliated, so Malcolm publicly humiliates himself and all of his classmates in order to level the playing field. Francis, Piama and Otto are horrified when when the Grotto gets a terrible review, and beg the reviewer to come back and give them a second chance. When they lose their collective temper with the awful man and end up beating him senseless, every other restaurant and hotel in the area thanks them and sends them customers. More...

Lois gets Malcolm a job at the Lucky Aid, and Malcolm sees a whole new side to his mother at work that he doesn't like. Reese gets a high-paying job cutting meat and loves it. Hal and jamie join a "Father and Me" type class which turns into a competition between all the dads and their kids. Dewey is fed up with the way he is treated by his older brothers at home, and goes to visit his good older brother, Franics. More...

Strapped for cash due to a cutback of hours at his work, Hal and the boys pool their money to buy Christmas trees to sell over the holidays. At the tree lot, they are forced to lower their prices in order to compete with the church down the block. When their business booms, two priests threaten them and send homeless people to their lot to scare customers away. Hal moves his business to his own front yard, but when one of his neighbors reports him, he is forced to move all the trees into his living room. Lois helps track down a possibly rabid squirrel that bit Craig. Francis and Piama are made homesick by watching Otto and Gretchen fight with their family over the holidays. More...

When Hal, Lois and the boys return home early from their vacation they discover their neighborhood holds an annual block party while they are away. Malcolm is horrified that their whole neighborhood hates them this much, so he tries to be helpful to a random neighbor loading his car. It turns out that Malcolm actually just helped someone rob one of his neighbors, but he then ends up busting those same neighbors for forging stock certificates. Hal and Lois compete in a kielbasa eating contest, and actually get their neighbors to rally around them. Reese comes up with a scheme to make money by letting the kids in the neighborhood beat him up, but he doesn't count on being betrayed by his partner in crime, Dewey. Francis might have his worst job ever; he has to use a fake cow rump to extract semen from bull. More...

As this month's editor of his high school literary magazine, Malcolm is amazed when a fellow student submits a well-written and moving piece of fiction. When his principal forbids Malcolm to publish it due to some dirty language, Malcolm calls the ACLU, and a hot-headed lawyer files a law suit against the school. Malcolm is blamed when the principal cancels all extra-curricular activities, but he sticks to his guns until the author of the story tells him not to fight anymore. Malcolm gives in to the principal, but publishes the story in his own "independent" literary magazine that he distributes just outside the school grounds. Hal's beautiful new boss flirts with him, and when he tells Lois about it, she encourages him to flirt back to keep his job. Reese tricks Desey into holding a pile of dirt and a rock for days, telling him it's a seed and he needs to make it grow. Francis teaches Otto to waltz for his 25th anniversary with Gretchen, but Otto finds he can only waltz with Francis for a partner.

Hal gets suckered into buying a hot tub, and he promises to keep it clean, but he doesn't and it gives him a horrible rash. Malcolm, with his new learner's permit, drives his babysitter, Polly, to the store, but she takes him on a detour to steal her dead mother's ashes from her ex-boyfriend.

Rating: 5.0/7

Grandma Ida (Cloris Leachman) arrives for a surprise visit and delivers shocking news to the family — she's getting married! Ida's fiancé, Mr. Li (James Hong), is a very wealthy and very old Chinese man she met on a cruise. Lois and Hal are supportive of her pending nuptials, because once the "I do's" are said, Ida and Mr. Li are moving to China — for good! Meanwhile, Malcolm secretly has his tongue pierced and it soon becomes infected, preventing him from saying any word with an S or a T. At the ranch, a third-rate acting troupe hams it up while performing a "murder-mystery weekend" play.

Rating: 3.8/5

Hal steals a job interview from a co-worker, but quickly regrets it when the company turns out to be some secret spy agency that scares him. Francis drives eight hours on his anniversary just to get his mother to apologize to him for calling him lazy on the phone. Dewey manipulates Reese into breaking Francis's record for stealing the most toilet seats out of the junkyard while avoiding nasty attack dogs. Francis tries to convince Reese that he shouldn't continue being self-destructive and stupid, just like their mother accuses them of being, but then he can't resist trying to get the record back by going back into the junkyard himself. Malcolm is going nuts, dealing with his mother both at home and at work, and it only gets worse when he plays on the Lucky Aid softball team that Lois is coaching. Malcolm is excited when he actually gets to play against his mother in the first match, but she manages to ruin what could have been a home run for him... in more than one way.

In the milestone 100th episode, Lois's younger sister, Susan, pays the family a visit and brings expensive gifts for the boys, including a '65 Mustang for Reese and Malcolm, and a cotton candy machine for Dewey. Hal removes the engine from the Mustang so that the boys won't drive it, but Reese and Malcolm coast it down a hill to a party to pick up girls. Unfortunately, when the party is busted by the cops, the engineless car blocks all the other kids' exit. Dewey barricades himself in the garage with the cotton candy machine and buries himself in pink fluff. Susan and Lois continue to bicker and one-up each other as they always do, particularly since Susan is still bitter about Lois stealing Hal from her. Lois finds out that Susan is in renal failure and needs a kidney, but Susan refuses to take a kidney from her sister. Lois goes under the knife and has her kidney removed, and then forces her sister to take it. Francis leads a Buttercup Troop for a weekend in the wilderness on the ranch, but he is quickly usurped as leader and eventually tied up and dragged by the girls to keep him quiet.

Malcolm decides to ask out a cute girl, Angela, who no one ever asks out. He finds out that's due to the fact that she has an "intrusive, overbearing, controlling and humiliating" family. Of course, Malcolm feels right at home with her crazy but very intelligent family, and actually enjoys spending time with them and playing games with them. Unfortunately, Malcolm loses his new family when he breaks up with Angela. Lois ruins her family's favorite past-time of going to Luigi's Pizza twice a month when she decides to protest Luigi's secret addition of a 15% service charge on their checks. Otto hires a young man named Jordan as an assistant for Francis. Francis becomes more and more helpless because Jordan is so good at doing things for him, including buttering his toast, holding a tissue to his nose, and thinking up smart retorts when Francis is talking to his mother on the phone. When Piama convinces Francis that he needs to fire Jordan, Jordan even lays himself off.

When Lois and Hal kick Reese out of the house, he decides to get his own apartment so he can live like a responsible adult. Although no one else seems to care, Francis is appalled that his parents would kick another child out and makes it his mission to show his parents their behavior is immature and unacceptable. Meanwhile, Malcolm helps Ira, a not-so-smart star football player, write his college essay. Ira takes the essay Malcolm writes for him to hand in as his own, and Malcolm has to decide whether or not to give up Ira. Guest cast: Jonny Acker as Ira, Jack McGee as Coach Oleski, Michael Dempsey as Teddy, Rod Spencer as Lou, Greg Zerkle as George, Patricia Belcher as Dr. Armstrong, Brian Mulligan as Mr. Noyes.

Rating: 5.3/8

Much to his dismay, Lois accompanies Malcolm on a college visit. When Lois discovers the dorm room is co-ed, she insists on sleeping there with Malcolm. While in the dorms, Lois clashes with the power-hungry resident advisor, Leland. Meanwhile, Reese pretends to be a drug dealer to get the attention of an attractive "narc" posing as a high school student. Hal denies Dewey a piano, so he starts stealing. Guest cast: Kenneth Mars as Otto, Stephanie Lemelin as Christie, Daniel Farber as Scott, Monique Coleman as Andrea, Andrew Reville as Leland, Jamie Renee Smith as Paula, Kelsey Chapman as Sally, Cole Peterson as Tony, and Steve Kramer as doctor.

Rating: 5.4/8

Hal sets up his friend Abe with Jamie's babysitter, Polly, and Lois sets Polly up with her co-worker, Craig. When Hal and Lois realize what they've done, they tell Polly she has to choose between the two miserable men, but Polly can't resist either of them. When Lois takes the family to a baseball card convention to see her favorite Polish baseball player, Pete Bucowski, Polly finds herself confronted with both her lovers. As Abe and Craig have a pathetic fight over Polly, Jamie wanders off. Polly decides not to choose either of the men, and instead chooses to concentrate on Jamie and her career as a babysitter... but Jamie's missing. Malcolm tries to convince Dewey that there is no such thing as a lucky shirt, despite all evidence to the contrary. At the baseball convention, even Reggie Jackson agrees that there is such a thing as luck. Malcolm makes a ridiculous bet to prove to Dewey that his shirt isn't lucky, but at the last minute regrets his decision and tries to steal the shirt. As they're fighting over the shirt, a lost Jamie falls from a vent in the ceiling and lands conveniently on the shirt that the boys are fighting over. Piama emasculates Francis in front of his workmen, and Francis complains to her, telling her he's losing the respect of the laborers. Piama actually tries to beef him up in front of the guys later, but when he takes the favor too far, she cuts him down and humiliates him even more. More...

So that Dewey won't suffer being in a Krelboyne class like him, Malcolm convinces him to do poorly on an I.Q. test. Dewey does so badly that he's placed in a class for the emotionally disturbed. Guilt-ridden and scared of what his mother will do when she finds out, Malcolm tries to get Dewey out of the class, and even goes so far as to tell Dewey's counselor that their mother has a substance abuse problem. Dewey, surrounded by weird but not stupid kids, is disgusted by the way his classmates are "handled" instead of educated. Dewey stages a rebellion and he and his fellow students raid another classroom for musical instruments, books, and art supplies. Reese tries to figure out if he might be some kind of genius too. Hal and Craig become obsessed with a dance video arcade game at a local pizza parlor. Otto accidentally blows up his truck instead of a dam. More...

In hopes of winning a national science competition, Malcolm and Stevie work on a chemistry experiment to create a new enzyme. Malcolm refuses to let Reese help, but while the boys are on a break, Reese tinkers with the experiment and gets it to work ... but of course doesn't remember how! Dewey sells candy for his school and to keep sales up he lies about what the money goes to. Hal fantisizes about the prizes the Dewey will win. Francis saves a runty piglet from being killed by naming it Ralph. More...

Lois and the boys visit her father's secret Canadian family, who are a mirror image of themselves – except they are PERFECT! Grandma Ida (Cloris Leachman) makes a surprise visit and will stop at nothing to get revenge on Victor's other wife, Sylvia (Betty White). Meanwhile, Hal and Dewey are set to take part in the school's father-son 5K race, until a fire extinguisher renders Hal temporarily blind. Guest Cast: Maura Soden as Roberta, Cloris Leachman as Ida, Wes Robinson as Jerome, Evan Bonifant as Scott, Betty White as Sylvia, Tom Virtue as Paragon Brush and Megan Hubbell as Jerome's Girlfriend.

Rating: 3.6/6

Part 1 of the season finale

When Hal refuses to cooperate with the FBI regarding a dishonest co-worker, he finds himself being framed for insider trading and placed under house arrest. Lois is forced to provide for the family by working 15-hour days, while proving Hal's innocence with a less-than-attentive defense attorney. Meanwhile, Reese catches his girlfriend cheating with Malcolm. Devastated, Reese runs away and joins the army with a fake ID, where he learns thinking is not all it is cracked up to be. Guest cast: Emy Coligado as Piama, Molly Orr as Beth, Erik King as Agent Stone, James Henriksen as Officer Moon, Steve Rankin as Sgt. Hendrix, Michael Chieffo as Dennis, Kevin Crowley as Tech, Paul Gleason as Mystery Man and Monti Sharp as Officer Joplin.

Rating: 4.6/7

Part 2 of the season finale

At home under house arrest, Hal awaits his pending trial. Convinced that he will be sent to the Big House, he doles out fatherly advice and words of wisdom to the boys. He also confesses to Malcolm that he was a terrible, lazy employee and admitted he called in sick every Friday for 15 years. Determined to prove his Dad's innocence, Malcolm realizes this is valuable information and devises a plan for the trial. Meanwhile, Lois is so stressed out by Reese's disappearance, Hal's arrest and the loss of her job that she finds herself in an almost catatonic state. And at boot camp, Reese uses skills he learned to combat Lois in order to win the field exercise.

Rating: 4.9/8