Kate is overjoyed when Diane and Jackie offer to let her have the kids on her first Mother's Day, however, when Kate discovers their hidden agenda -- she is determined to get revenge.
Kate begrudgingly agrees to accompany Jackie to her high school reunion, not fully realizing all that it entails.
Kate tries to help Warren improve his social life, but her efforts backfire.
The Kate-Diane power balance flips after Kate publically saves Diane’s life. But when a now over-confident Kate gets in trouble at the PTA meeting, she needs Diane to help get her out of it.
In order to get some time to themselves, Pete and Kate lie to Jackie and Diane about being in couples’ therapy. The exes catch on to their trick and confront Pete for lying in order to avoid conflict. Kate rises to his defense—that Pete has changed in his relationship with her—but when Diane tells her that he switched Kate’s awful chili out for his own special recipe for Warren’s Pioneer Day, Kate gets upset. Meanwhile, when Meg stays over to avoid Tevin, Hillary studies Meg for a psychology project on arrested adolescence.
Kate persists in planning her dream wedding despite the added chaos from the arrival of her mother Cricket (guest star Megan Mullally) and Pete’s parents. However, things come to a screeching halt when the family gets some bad news.
When Kate finds Pete’s old wedding videos, she realizes she wants a wedding of her own. But as the preparations begin, Kate discovers she’s in the country illegally. This triggers a visit from an INS agent, and Kate and Pete must prove they’re not in a green card marriage. Meanwhile, Jackie struggles with telling Bert she’s dating Sad Steve.
Kate uses Bert’s birthday party as an entree into the exclusive soccer mom clique. Meanwhile, Diane refuses to admit she made a mistake when she makes an illegal left turn, and Warren develops a guy crush on the object of Hillary’s affection.
Jackie pitches a business idea to Pete, which he dismisses because of her poor entrepreneurial track record. But Kate thinks it’s a good idea and partners up with her. Warren and Bert take karate lessons with Pete. When Pete learns the boys wanted to sign up because they think Pete is too non-confrontational, Pete has to prove to his sons that he’s tough. Meanwhile, Hillary deciding to try out for track brings out Diane’s competitive side.
When Bert loses a tooth, Kate learns of Pete and Jackie’s elaborate Tooth Fairy rituals. The fact that Kate doesn’t share their excitement makes her question her maternal nature. However, in helping Warren with his first study date, Kate finds she’s more maternal than she thought. Meanwhile, when Hillary invites friends over to Diane’s house, she becomes nervous her mother will ruin the evening for her.
When Warren and Hillary misbehave on Kate’s watch, Diane convinces Kate to actually punish them for once. Kate lays down a harsh sentence...which the kids are able to exploit to “punish” her. Meanwhile, Pete and Jackie realize their hostility toward each other might be affecting Bert, and they try to be civil for an entire round of mini golf.
Kate tries to break Pete’s lifelong streak of horrible birthdays, but it seems the curse is very hard to break. Meanwhile, Diane and Jackie spend the day together looking for a birthday gift for Pete.
When all the presents go missing on Christmas morning and none of the parents can remember where they are, the family goes on a mission to piece together the mystery of what happened the night before Christmas. Along the way, Kate and Jackie team up to give Diane the perfect Christmas gift and Pete trades in his Grinch-like attitude and embraces the true spirit of Christmas.
Kate tries to play matchmaker to Diane and another parent on Warren’s field trip, but is shocked by what she learns in doing so. Meanwhile, Jackie takes it upon herself to care for Pete when he’s sick – but she finds herself more interested in having the run of the house. Also, Hillary’s educational skits and songs upstage Bert in his own classroom.
When lice attack the Harrison household, Kate and Jackie band together to show Diane that she isn't great at everything she does. Meanwhile, Warren and Bert fight about custody of a teddy bear.
When Jackie has a drunken encounter with one of Pete’s coworkers at Kate and Pete’s party, Kate and Pete deal with the ensuing awkwardness. Meanwhile, Warren and Bert try to attract more viewers to their live-streaming gum show, and Meg helps Diane with a secret mission.
When Jackie’s homemade costume nearly ruins Bert’s Halloween, Kate steps in with the costume he wanted, and Bert’s so overjoyed that he asks Kate to take him trick-or-treating. This leads to a fallout between Jackie and Kate, which gets worse when Bert goes missing. Meanwhile, Pete tries to get a neighborhood teen to admit he egged Pete’s house last Halloween.
Finding it more and more difficult to spend time alone and away from Diane’s constant demands, Kate and Pete sneak away for a romantic tryst at the school fundraiser. But when they get trapped, truths come out and Kate reveals she wants to be at the top of Pete’s priority list and for him to stand up to Diane. Meanwhile, the kids help Jackie with her online dating profile.
When Meg needs Kate’s help getting through a breakup, Kate finds herself torn between her obligations as a friend and her responsibilities as a wife and step-mom. Kate struggles to be a good friend to Meg, but when Meg’s breakup drama gets to be too much, it leads to a falling out between them. Meanwhile, Warren figures out where his true talents lie when Jackie enlists his help with Bert’s Lego project.
When Hillary starts sneaking around on the weekends, Pete overreacts and makes matters worse. Kate tries to take over, but she finds that her own parental style needs work. Meanwhile, Jackie tries to finagle a jewelry deal with a parent of one of Bert’s classmates.
Wanting to find her role in the family and feel needed by the kids, Kate pitches in and puts Bert to bed. Unfortunately, her methods result in Bert getting freaked about his uterus. Kate tries to cover up the mistake, which only makes things worse. When Hillary and Warren spill on Diane’s favorite couch, they conspire to try and evade Diane’s famously crafty punishments.
When Kate falls in love with the man of her dreams, she finds herself in over her head juggling her new responsibilities and new relationships with his three children and two ex-wives. After embarrassing herself at a parent-teacher conference, Kate makes a bold move to help her stepdaughter hide a secret. Meanwhile, Pete and Jackie conspire to hide the death of a pet hamster, and Bert bullies Meg into buying him a new Lego set.