Gracen wonders aloud how his lovely "house flipper" wife, Leila, can afford to buy a $200 designer toaster and how his deadbeat son, Marmaduke, who struts around the house in nothing but his jockeys and a smile, suddenly lands an internet job making more than his dad. By the end of the day, the guys have their mission: to steal back the respect Gracen deserves by any means necessary.
Laird pretends to be married to impress a girl who's into married men. Dougie believes Aubrey is having an affair when he sees him sneaking into a motel. Marmaduke suspects that Laird is his father.
Gracen gets more than he bargained for when he tries to spice up his sex life with Leila. Especially when she reveals that she fantasizes about Laird. This causes problems in the carpool.
Leader-of-the-pack Laird loses his stud status when he learns his sperm count is low and Gracen's is high. Meanwhile, Dougie is reduced to doing manual labor for Aubrey to score a spot in a pre-school, and Marmaduke navigates the modern day world of bartering.
Laird hooks up with his hot but crazy ex-wife, Joannifer, who disrupts all of the carpoolers' lives. Dougie and Cindy decide to renew their wedding vows to wipe out the memory of their catastrophic first wedding ceremony.
The guys feel guilty but swear secrecy when they believe that a prank they pulled caused a rival carpool's car to catch fire. Meanwhile, Marmaduke’s latest money making venture, an ATM machine that levies an $8.00 service charge, is cut short after being vandalized by unsatisfied customers.
Laird is infatuated with the sexual harassment seminar leader, Dorrit. To guarantee time alone with her, he claims he's being sexually harassed by the women in his office. Meanwhile, Leila enlists Marmaduke's sign spinning skills to promote her real estate business, but he has to out-spin the competitors on the same street corner.
Dougie wins tickets to see his favorite rock band, the Spin Doctors, but Cindy refuses to go because she doesn't trust anyone to baby sit their infant. Leila distributes flyers door-to-door in an effort to boost her real estate career, but a typo identifies her as a hooker; and Laird adopts a neighborhood dog who turns out to be a wild, dog-eating coyote.
Laird fears he may be losing his looks when he meets someone who's been dubbed 'the handsomest man' in his office building, so to make himself more interesting to women, Laird starts to take clarinet lessons. In the meantime, while guarding one of Leila's properties, Marmaduke falls for the girl who tagged Leila's flip.
When there are no parking spots available at the carpool lot, Laird decides to take a handicapped spot and forces Gracen to pretend he can't walk to his office. When a parking attendant discovers the hoax, the guys not only lose their carpool privileges, the bad karma keeps on coming --- Gracen refuses to ride with Laird, and Laird is accused of sexual harassment by Aubrey's favorite babysitter.
Aubrey invites the carpoolers to his daughter's piano recital and Dougie accepts for a reluctant Gracen and Laird, which causes the group to examine their friendship. Meanwhile, with Marmaduke's visualization coaching, a determined Gracen trains heavily to finally beat wife Leila in an annual charity run.
When Gracen refuses to support Marmaduke's newest business venture -- a lawn-cutting business using a flock of sheep -- Marmaduke moves in with Laird, who enjoys being a "dad" to Marmaduke, but this "father/son" bond causes a rift between him and Gracen.
Aubrey brings his daughter, Michelle, to work for "Take Your Daughter to Work Day," but gets fired when he's caught pretending to be his boss, and Cindy is possessed with power making big bucks selling Green Queen products.