: Reese attempts to live on his own in an apartment and eventually makes a massive life change by enlisting in the Army during the season finale.

: The family discovers their neighbors have been throwing a celebratory party every year specifically because the Wilkerson family is away on vacation.

: Malcolm tries to prevent Dewey from being placed in the high-stress Krelboyne class, but Dewey's plan to fail the IQ test backfires, landing him in a class for emotionally disturbed students.

: Following his birth at the end of Season 4, Jamie becomes a central figure, leading to new dynamics like "baby gambling" among local fathers and Lois struggling to maintain her usual level of control.

: A two-part finale where Reese runs away to enlist after a heartbreak, and Hal faces potential jail time for his company’s legal troubles. Main Cast & Guest Stars Frankie Muniz Bryan Cranston Jane Kaczmarek Justin Berfield Erik Per Sullivan Christopher Masterson Notable Guest Cloris Leachman as Grandma Ida Notable Guest David Cassidy as Boone Vincent

: Directed by Bryan Cranston , this episode features Malcolm and Stevie needing the "unintelligent" Reese to help solve a complex scientific enzyme problem.