Christine feels pressured to throw an extravagant party for Ritchie's 9th birthday, his first involving other children from his new private school. Recoiling from sticker shock after meeting with a ritzy event planner, Christine decides to have an arts and crafts party at her home, with mixed results.

Christine's former marriage counselor comes into the gym, leading to some awkward moments between the two women. When Christine mentions this to Richard, his cryptic reaction leads her to question whether it was in the counselor's best interest to encourage their divorce. Meanwhile, Matthew finds Christine's wedding video in a box of old photo albums, and Christine takes a trip down memory lane.

Christine has been burning the candle at both ends -- working hard and trying to be a good mom. Ritchie decides he wants to join the reptile club at school and tells Christine all she needs to do is get the permission slip in on time. When Christine realizes that she's forgotten yet again, she asks the Reptile Guy (Jeffrey Tambor) to make an exception. He says the only way he'll consider is if Christine will go on a date with him. As creepy as he is, Christine is determined not to let Ritchie down, and so she complies.

After Ritchie hurts himself at a skateboarding party, Christine accuses Richard of bad parenting, and they begin competing to prove each other wrong. Matthew gets involved in a rebound relationship.

Christine and Richard help Marly and Lindsay through labor, bring back memories of Ritchie's birth which, in turn, brings back feelings for one another.

After the mothers at Ritchie's private school continue to take cheap shots at Christine, Christine decides to enroll him in public school.

Mathew gets assistance in losing weight from fitness 'expert' Christine, but she soon realizes she can't shed off a few pounds herself.

Hoping to show she's fine with Richard and New Christine's wedding, Christine feigns being in love with Todd Watski—a ruse that proves difficult to pull off when he acts boorishly at the rehearsal dinner. Meanwhile, Matthew has an encounter with New Christine's sister, Amy.

The parent company of Christine and Barb's gym franchise comes for an inspection and discovers that they have broken a contractual clause, risking the entire business. New Christine wants Richard to get a vasectomy.

After Richie begins showing more interest in spending time with Richard and then does a bad job on his school homework project, Christine contemplates bailing Richie out in an attempt to win him over again.

Christine vows to become more aware of politics when Richard scolds her about her indifference towards an upcoming election setting a bad example for Ritchie.

When Christine learns that Richard has been hired to remodel "meanie mom" Lindsay's bathroom, she can't help but intervene to make sure he doesn't screw up the job and risk their reputation at Ritchie's school. Additionally, she and Richard are at odds over which of them gets to be the one to give Ritchie the sex talk.

Christine can't help but meddle in Matthew's love life when she meets his ex-girlfriend at a party. Meanwhile, Richard hopes to get Ritchie enthused about his contracting job.

When Christine's environmentally-friendly hybrid car and Marly's gas-guzzling monster SUV hit one another, it becomes a bigger dispute than simply who hit whom. While her car is in the shop, Christine is forced to go against her principles and rent a luxury SUV when no other car is available.

Ritchie goes to church with Richard and new Christine without consulting his mother first, leaving old Christine to explain and explore her aversion to organized religion.

Richard want Ritchie to learn the value of competition and male bonding, and signs him up for soccer. Christine disagrees, but then has her own competitive urges when fighting with Richard for attention from Mr. Harris.

Jealous that New Christine benefits from all the positive qualities she instilled in Richard during their marriage, Christine spites her by revealing to Richard that she gave New Christine the idea for the birthday gift she gave him.

Christine finds out Richard's brother is gay, but not until after sleeping with him.

On their way to Ritchie's desert camping trip, Christine, Richard, Matthew, and Barb stay at a seedy motel and get on each others' nerves.

Roles reverse when Christine's dubbed a "meanie mom" by a father at Ritchie's school who finds Marly and Lindsay to be to his liking.

Christine has trouble working with Barb at the gym and feels pressure at home to find a nanny for Ritchie when Richard is unavailable to care for him due to a trip with New Christine.

Christine finds out her new sleep medication caused her to embarrass herself over the phone.

Christine realizes that Ritchie has never been on a real family vacation, so she plans a trip to Florida, with disastrous results.

Christine's 8-year-old son, Ritchie has been accepted into a posh private school where Christine encounters two snooty class moms, Marly and Lindsay, who can't seem to grasp the concept that Christine actually works. Her 20-something slacker brother, Matthew, lives with her, but in a pinch, also serves as Ritchie's babysitter. On the first day at Ritchie's new school, Christine is mortified to discover that her ex-husband, Richard, with whom she gets along even better than when they were married, is dating a young, nice, impossible-to-hate woman also named Christine… the "new" Christine.

Following Christine's breakup with Burton, everyone expects Christine to fall apart emotionally, but she insists she is fine and looking forward to spending time with her best friend: "me." But after being humiliated while dining out alone, Christine realizes she really did care for Burton, which drives her even crazier.