When Lois thinks she might be pregnant again, she and Hal argue...and remember how their lives changed with the births of each of their sons.

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 though a date with a geeky 12-year-old.

Malcolm, Reese, Dewey, and Stevie sneak out to a county fair, then get locked inside after hours with a drunk, belligerent guard.

The younger boys try to convince Lois to let them have a mini-bike; Hal attends a father-son weekend at Marlin Academy.

Francis forces Malcolm and Reese compete to "earn a coveted ticket to a wrestling match; Dewey loses Craig's cat while Craig is away at a comic book convention.

Malcolm and Reese's trip to a bowling alley is seen in two versions; one with Hal chaperoning and one with Lois doing the honors.

Malcolm tries to help Reese bring his grades up; Francis is exiled to a friend's house after defying Lois' order to patch the roof.

Reese discovers a talent for cooking; Malcolm tries to convince a Krelboyne classmate not to have a party; Francis is forced to write a term paper.

Malcolm is hospitalized for an appendectomy; Francis stages a hunger strike at Marlin Academy.

Lois disputes a cop's claim she was driving recklessly, and orders Francis to pay off $750 in parking tickets he racked up under her name.

Lois' disapproving parents visit; Francis goes to Mardi Gras but gets stopped by food poisoning.

Hal quits his job to become an artist; Francis suffers though a week of inventory work at Lucky Aide; and Malcolm begins to wonder about his own career future.

New neighbors, who turn out to be even more awful than Malcolm's family, move in next door; the Marlin Academy cadets prepare for a visit from Oliver North.

Malcolm experiences his first crush as a confusing mix of love and hate; Francis tries to avoid discipline for his latest prank; Dewey overreacts to Lois' lecture about the hazards of dirty teddy bears.

Malcolm gets in trouble with an elderly neighbor; Francis' slacker friend enrolls at Marlin Academy; Dewey trades his backpack for a purse.

When Reese gives up his position as school bully, Malcolm suffers at the hands of his successors; Francis dreads his upcoming birthday at Marlin Academy.

Malcolm's friendships suffer when he becomes the suddenly popular star of a high school play; Hal and Dewey build their very own Utopia from plastic blocks.

Malcolm gets into therapy to get out of class; Francis cleans up on laundry duty; Dewey turns out to be a skittles prodigy; and Hal and Lois attempt to clean out an over-stuffed closet.

While Hal and the boys are besieged by bats after Hal brings home an antique armoire; Lois gets robbed at work.

Malcolm and Reese compete with Dewey for a cute babysitter's attention, while Hal and Lois attend a convention where Hal can't resist fighting with an old rival.

When the family takes a vacation to a casino, Hal gets banned from gambling and takes Malcolm and Reese on an ill-fated trek into the desert; Lois and Dewey win a free day of spa pampering.

Malcolm's family goes out to dinner with the straight-laced Kenarbans, while Francis makes the mistake of inviting local girls to a party at Marlin Academy.

When the boys demolish Lois' meager hopes for a happy birthday, she runs away from home.

Malcolm and his brothers build the ultimate stealth weapon, while Hal and Lois battle a speeding car that terrorizes their neighborhood.

Stranded in a traffic jam, Malcolm meets his match in an intriguing young girl; Reese attempts to break into an ice cream truck; and Lois tries to control the uncontrollable chaos.