Malcolm's cushy babysitting job provides relief from the trailer the family's using while their house is being fumigated, until Malcolm learns that the trust placed in him in his new position is strictly limited. Meanwhile, the military school's master key leads Francis to a corpse, for which he provides a proper send-off.

A relative's funeral conflicts with Malcolm's plans for his very first date, so he tries to figure out a way to skip the bereavement ceremony.

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.

Malcolm gets a role in the high school play and is so captivated by high school gossip that he forgets his lines. Lois discovers the joys of massage. Hal and Dewey build a society of model buildings in the living room. Francis tries to show his individualism at school when the commandant cracks down on personal belongings.

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.

A hospital stay unsettles Malcolm, who's stuck in a kids ward with what may be appendicitis. Meanwhile, at military school, Francis leads a hunger strike.

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.

The return of the smart and sassy Cynthia rattles Malcolm, who's astonished by her physical maturation. And so is drooling Reese.

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.