Lois tags along with Malcolm as he visits a college, but she's determined to room in the dorm Malcolm is staying in when she learns the room is co-ed.
Meanwhile, after his father denies him a piano, Dewey begins stealing objects from around the house to amuse himself and to drive Hal crazy.
Reese meets a girl, who he thinks is a narc, and he pretends he is a dealer, unaware that she is really an undercover cop.
Malcolm is a regular high school kid trying to navigate his way through life despite the various obstacles thrown in his way a complete misunderstanding of girls, the constant burden of masterminding plans to get himself and his brothers into or out of trouble, and a miserable job at the Lucky Aide not to mention a severe case of teen angst.
Although Malcolm has a genius IQ, he can't seem to make sense of the opposite sex, much less his embarrassing family. Lois is the outspoken, opinionated mom, who still manages to rule the roost even though her boys are growing wise to her crafty ways. Hal, a dad who is just a bumbling, big kid at heart, often finds himself creating more chaos than his five boys combined.