After spending years as a full-time mom, Katie goes back to work as a party planner, which brings new challenges of balancing home and work life into the mix.
With her new job taking up more of her time, Katie and Greg try to split up parenting duties. Katie over-involves herself in Taylor's social life by trying to keep some distance between Taylor and her boyfriend, Trip, to make sure Taylor is her own person aside from him. Meanwhile, Greg tries to convince Oliver to be honest after overhearing Oliver lie to his friends about his less-than-luxurious summer vacation.
When Katie's mom, Kathryn, comes to town, Katie and Kathryn encourage the kids to make less than favorable decisions: Oliver cheats in shop class and Katie helps him try to get out of it, while Kathryn reassures Taylor that she doesn't need to go to college.
Anna-Kat runs for the Green Chair position in the school election against Chloe Brown Mueller's daughter, which results in Katie and Chloe turning their kids' election into a feud of their own. Meanwhile, Greg becomes concerned that Taylor's new friend Pierce is trying to steal her away from Trip, causing Greg to intervene and scheme to prevent it.
When Taylor decides she wants to go to a Halloween party, Greg and Katie disagree on whether or not Taylor can be trusted. Oliver and Cooper anxiously try to prepare for playing a game of "seven minutes in heaven" with their dates at a separate Halloween event. A pregnant Viv follows Katie around trying to get help preparing for her baby's arrival.
After the previous "fattest housewife" in Westport gets plastic surgery to lose weight, Chloe Brown Mueller rubs it in Katie's face that Katie has now assumed that title. In order to get revenge on Chloe, Katie goes through great lengths to dig up bad photos of Chloe from high school. In discussing body image with the kids, Katie and her mother, Kathryn, turn out to be bad influences on Anna-Kat and Taylor, unintentionally encouraging them to focus too much on the outward appearance. Over time, Katie realizes how judgmental she has become and that she is part of the problem.
After discovering that the four digit pin code the Otto family uses for everything spells out Greg's ex-girlfriend's name, Katie gets upset and retaliates by dragging out old gifts from past boyfriends. Meanwhile, the kids' current love lives take a hit as Taylor and Trip argue over her relationship with Pierce; and Oliver and Gina's relationship goes south when they both apply for a ballet scholarship that only one of them gets.
Katie lands the perfect pawn to play on the insecurities of the Westport housewives when she convinces a hot young trophy wife named Harper to volunteer as room mom for Anna-Kat's class, but she quickly shifts gears when Harper rejects Anna-Kat's idea for movie night. Meanwhile, Greg enlists the help of the kids to get Katie's mom, Kathryn, to take an interest in someone other than herself.
Oliver and Taylor stumble through their love lives, making Katie miss the spontaneity and unpredictability of being young and in love. Meanwhile, Kathryn's plan to soothe Oliver's heartbreak backfires when she tracks down an old boyfriend, Dan, and he is not as she remembers. At the same time, Anna-Kat makes strides at school when Franklin is stuck at home with the chickenpox, forcing her to make a new friend.
Katie strives to keep her long-separated parents apart when her father arrives in time to surprise the Otto family for Christmas. Anna-Kat does her best to help Trip win Taylor back but has a hard time getting past a very persistent Pierce. Meanwhile, Oliver thinks no one will remember him as the mask-wearing villain in the school's production of "The Nutcracker" but quickly takes center stage when a series of mishaps damages his costume.