The series takes place 19 years after the final episode of the original series. Malcolm has built a new life with his daughter Leah and his girlfriend Tristan, having deliberately shielded them from his dysfunctional family for over a decade. This carefully cultivated tranquility is shattered when Hal and Lois insist that he attend their 40th wedding anniversary celebration with his new family. Chaos inevitably ensues when Malcolm is forced to reunite with his eccentric parents and brothers.