In the milestone 100th episode, "Lois' Sister", Lois' younger sister, Susan (Laurie Metcalf), pays the family a visit and brings with her expensive gifts for the boys, biting remarks for Lois and a cold shoulder for Hal â- whom she has never forgiven for dumping her for Lois. Lois and Susan's competitive relationship takes a turn for the worse when Susan gives Malcolm and Reese her prize '65 Mustang convertible. But when Lois discovers that Susan needs a kidney transplant, she puts her anger aside and offers to donate her kidney to Susan, which Susan only sees as the perfect opportunity for Lois to one-up her.

Malcolm in the Middle Season 5 Episodes...

• s05e01 - Vegas
• s05e02 - Watching the Baby
• s05e03 - Goodbye Kitty
• s05e04 - Thanksgiving
• s05e05 - Malcolm Films Reese
• s05e06 - Malcolm's Job
• s05e07 - Christmas Trees
• s05e08 - Block Party
• s05e09 - Dirty Magazine
• s05e10 - Hot Tub
• s05e11 - Ida's Boyfriend
• s05e12 - Softball
• s05e13 - Lois's Sister
• s05e14 - Malcolm Dates a Family
• s05e15 - Reese's Apartment
• s05e16 - Malcolm Visits College
• s05e17 - Polly in the Middle
• s05e18 - Dewey's Special Class
• s05e19 - Experiment
• s05e20 - Victor's Other Family
• s05e21 - Reese Joins The Army (1)
• s05e22 - Reese Joins The Army (2)

Malcolm in the Middle Show Summary

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.