Malcolm finds his life as the middle brother in an eccentric family made even more difficult by his being placed in a class for gifted students at school where he reluctantly befriends another boy with a high IQ and stands up to a bully.

Parallel stories pit Malcolm against a bullying, obnoxious new kid and Francis vies with his intimidating, military-school commandant, who's presenting sex-education lectures. Meanwhile, Hal takes heat after cutting down a tree.

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.

Lois's firing prompts household economizing. Meanwhile, Francis delights in his honor-guard duty—at a teenage beauty pageant.

While Hal secretly takes the boys to the stock car races, Lois desperately searches for her missing paycheck. Francis at military school is keeping a boa constrictor as a pet.

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.

A spiffy cheerleader attracts slovenly Reese, who cleans up his act—best as he can—to woo her. He even joins her rah-rah squad. Dewey tries to convince Lois and Hal to buy him a new toy. Francis has a heart-to-heart conversation with headmaster Spangler.

Malcolm's humiliation as a Krelboyne drives him crazy, so he fakes his way into seeing the school's shrink, with whom the con continues.

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.